Multi-path converter and control method therefor

ABSTRACT

The present invention relates to a multi-path converter, which adds a current transfer path using a capacitor to a current transfer path using an inductor to supply a current that is output to an output end (load) to a plurality of parallel paths, thereby reducing a total RMS current flowing through the inductor, and a control method therefor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. Application No. 17/843,689 filed Jun. 17,2022, which is a continuation of U.S. Application No. 16/591,145 filedOct. 2, 2019, which is a continuation-in-part of PCT/KR2018/003301 filedMar. 21, 2018, claiming priority based on Korean Patent Application No.10-2017-0042876 filed Apr. 3, 2017, Korean Patent Application No.10-2017-0083619 filed Jun. 30, 2017 and Korean Patent Application No.10-2018-0015712 filed Feb. 8, 2018, of which the disclosures areincorporated herein in their entireties.

TECHNICAL FIELD

The present invention relates to a converter having multiple paths and acontrol method thereof, and more specifically, to a converter forconverting a voltage of input power to output the converted voltage to aload, and a control method thereof.

BACKGROUND ART

As the number of applications applied to electrical and electronicdevices is increased and functions of the electrical and electronicdevices are increased, power consumed by the devices is increasingcontinuously. Accordingly, power management circuits that supply powerrequired by the devices should be designed to have high power efficiencycharacteristics in high power applications. This is because a powermanagement circuit having high power efficiency not only increases ausage time of a device but also reduces heat generated in the powermanagement circuit in the device.

The conventional power management circuits are mainly designed throughtwo methods. One method is a switched capacitor or charge pump methodusing a capacitor, and the other method is a switched inductor methodusing an inductor.

First, since the switched capacitor method does not use a bulky inductorand uses a capacitor that is advantageous in being embedded in a chip ascompared with an inductor, there is a great advantage that an area of aprinted circuit board (PCB) may be reduced. However, since a practicablevoltage conversion ratio (V_(OUT)/V_(IN)) is discontinuous in theswitched capacitor method, a high efficiency characteristic may beachieved only at a specific voltage conversion ratio. Therefore, inorder to increase a practicable voltage conversion ratio to implement ahigh efficiency characteristic in a wide voltage range, a powermanagement integrated circuit (PMIC) should be designed as areconfigurable type, which increases complexity of a system. Inaddition, when a load current (I_(LOAD)) is increased, since capacitanceof a capacitor constituting a converter should be increased, thecapacitor may not be integrated in an integrated circuit (IC), and thus,a plurality of external capacitors may be required. As a result, theswitched capacitor method may consume a larger area of a PCB as comparedwith the switched inductor method. Therefore, the switched capacitormethod is mainly used in low power applications.

On the other hand, a power management circuit using the switchedinductor method is bulky and uses an inductor that is relativelyexpensive as compared with other external devices, there are manyadvantages to the switched capacitor method in that a practicablevoltage conversion ratio is continuous and a high efficiencycharacteristic is implemented in a very wide range. In addition, sincethere is no additional external device even when a load current isincreased, the power management circuit using the switched inductormethod is indispensably used in various modern devices of which powerconsumption is increasing.

FIG. 1 is a diagram illustrating an example of the conventional powermanagement circuit using the switched inductor method. FIG. 2A and FIG.2B show diagrams for describing a method of improving efficiency of theconventional power management circuit shown in FIG. 1 .

As shown in FIG. 1 , when a load current I_(LOAD) is increased, acurrent I_(L) flowing in an inductor is also increased. A parasiticresistor (R_(DCR)) connected in series with the inductor is inevitablyincluded in the inductor, and as a level of the current flowing in theinductor is increased, power loss caused by the parasitic resistor isconsiderably increased. The power loss limits efficiency characteristicsof the power management circuit and causes heat generation. Therefore,in order to increase power efficiency, it is preferable to use aninductor having a small parasitic resistance value as shown in FIG. 2A.In this case, a volume or unit cost of the inductor is increased.

In particular, in the case of a power management circuit to be includedin a mobile device that is being continuously miniaturized, a volumethereof is also restricted according to a size of a device to bemanufactured. Thus, an inductor indispensably used in aswitched-inductor power management circuit is also limited to anultra-small inductor (having a height ranging from 1 mm to 1.5 mm). Thatis, as described above, it is impossible to use a bulky inductor whichhas a small parasitic resistance value. Therefore, it is necessary touse a smaller inductor for the same inductance to satisfy volumecharacteristics of a mobile device, but a small inductor includes a verylarge parasitic resistor. To improve efficiency under such conditions,as shown in FIG. 2B, there is a method of using a plurality of inductorsin parallel. This method reduces a level of a current flowing in eachinductor, thereby reducing the total current loss caused by a parasiticresistor. However, since the method requires the plurality of inductors,a volume and a unit cost are increased. Also, a circuit for controllinga current to be divided to each inductor is additionally required,thereby increasing complexity of a system.

In addition, in the case of the conventional buck-boost converter andboost converter, since a current is not supplied to a load while acurrent in the inductor is built-up, a current supplied to the load isdiscontinuous. Accordingly, a level of the current in the inductorshould be much greater than that of a load current, which requires aninductor with a high saturation current value. In addition, thediscontinuous supplying of a current generates a large ripple voltage atan output voltage terminal and causes a switching spike.

DISCLOSURE Technical Problem

The present disclosure is directed to providing a multi-path converterin which a current transfer path using a capacitor is used in additionto a current transfer path using an inductor. As such, a current flowsthrough a plurality of parallel paths to an output terminal (i.e.,load), thereby reducing a total root mean square (RMS) current flowingin an inductor, and a control method thereof.

Technical Solution

The exemplary embodiments may provide a converter including: an inputunit; an output unit; and a conversion unit configured to convert avoltage of power input through the input unit and transfer the convertedvoltage to the output unit by transferring a current to the output unitthrough a plurality of parallel current transfer paths including atleast one inductor and at least one capacitor.

The plurality of parallel current transfer paths may include a firstcurrent transfer path including at least one inductor and a secondcurrent transfer path including at least one capacitor.

The plurality of parallel current transfer paths may include more thanone of the first current transfer path or more than one of the secondcurrent transfer path.

The first current transfer path may further includes at least onecapacitor.

The conversion unit may periodically perform an operation including aplurality of conversion operation modes, and the conversion unit maydivide and transfer the current to the output unit through the pluralityof parallel current transfer paths in at least one of the plurality ofconversion operation modes.

The conversion unit may function as one of a step-down converter, astep-up converter, and a step-up-and-down converter.

The converter may include a plurality of conversion units which convertvoltages concurrently in different conversion operation modes.

The converter may include a plurality of output units including theoutput unit, and the conversion unit may convert the power input throughthe input unit to transfer the converted power to each of the pluralityof output units.

The conversion unit may perform a function of a step-up converter withrespect to some output units of the plurality of output units and mayperform a function of a step-down converter with respect to remainingoutput units of the plurality of output units.

The converter may include a plurality of conversion units including theconversion unit, and the plurality of conversion units may be connectedin series, parallel, or series-parallel with each other.

The conversion unit may transfer the current to the output unit whilethe voltage of the input power is converted.

The exemplary embodiment may provide a control method of a multi-pathconverter including converting a voltage of power input through theinput unit by transferring a current to the output unit through aplurality of parallel current transfer paths using at least one inductorand at least one capacitor.

The plurality of parallel current transfer paths may include a firstcurrent transfer path including at least one inductor and a secondcurrent transfer path including at least one capacitor.

The parallel current transfer paths may include more than one of thefirst current transfer path or more than one of the second currenttransfer path.

The first current transfer path may further include at least onecapacitor.

The transferring may include periodically performing an operationincluding a plurality of conversion operation modes, and the current isdivided and transferred to the output unit through the plurality ofparallel current transfer paths in at least one of the plurality ofconversion operation modes.

The current may be transferred to the output unit while the voltage ofthe input power is converted.

According to an exemplary embodiment, a step-down converting methodincludes operating a step-down converter including a power source, aninductor, a capacitor, and a load in a multi-path manner and operatingthe step-down converter in a single-path manner. In the operating in themulti-path manner, a current is transferred to the load through aplurality of parallel current transfer paths, and in the operating inthe single-path manner, a current is transferred to the load through asingle current transfer path.

Advantageous Effects

According to the exemplary embodiments, since a current is divided andsupplied to a load through an additional current transfer path using acapacitor, a root mean square (RMS) current flowing in an inductor canbe reduced as compared with when a static current is supplied to theload (i.e., output terminal) by using only an inductor. Therefore, whena level of a load current is increased, it is possible to greatly reducepower loss caused by a parasitic resistor of an inductor which has thegreatest power consumption in a power management integrated circuit(PMIC) for mobile applications. As such, it is possible to overcome alimitation of power efficiency which is not overcome by any conventionalpower management circuit technology.

According to the exemplary embodiments, since a capacitor having arelatively small volume and low unit cost as compared with an inductoris used as an element for distributing a current, it is possible toreduce a volume and a cost. Furthermore, a capacitor has a very lowparasitic resistance value of about several mOhms as compared with aninductor which includes a serial parasitic resistor having a very highparasitic resistance value of about several hundred mOhms. Thus, powerloss occurring in an additional current path using a capacitor is lessthan power loss in a current path using an inductor. In summary, aninductor structure according to the exemplary embodiments has a highefficiency characteristic. In addition, the inductor structure canincrease a usage time of a device, greatly reduce heat generated in apower management circuit, and also reduce consumption of an area andvolume of a printed circuit board (PCB).

Furthermore, according to the exemplary embodiments, since a current isdivided and supplied to a load through an additional current transferpath other than a current path through which a current flows to theload, power loss can be reduced as compared with a conventionalstep-down converter, thereby increasing efficiency. Consequently,according to the exemplary embodiments, under a condition of having thesame efficiency as the conventional step-down converter, it is possibleto increase efficiency as compared with the conventional step-downconverter and also provide an output voltage in the same range as thatof the conventional step-down converter.

According to the exemplary embodiments, a partial current is allowed toflow to an output terminal even while input power is stepped up, therebyreducing the current in the inductor to improve efficiency, reducing aripple, and reducing switching noise due to a continuous current flow.Therefore, according to the exemplary embodiments, it is possible toprevent a reduction in performance of a load connected to an outputterminal of a step-up converter, that is, performance of a block towhich a high voltage formed by the step-up converter is applied.

DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating an example of a conventional powermanagement circuit of a switched inductor method.

FIGS. 2A and 2B show diagrams for describing a method of improvingefficiency of the conventional power management circuit shown in FIG. 1.

FIG. 3 is a block diagram illustrating a converter with a multi-pathaccording to an exemplary embodiment.

FIG. 4 is a diagram illustrating an extended example of the multi-pathconverter shown in FIG. 3 .

FIG. 5 is a diagram illustrating another extended example of themulti-path converter shown in FIG. 3 .

FIG. 6 is a diagram illustrating still another extended example of themulti-path converter shown in FIG. 3 .

FIG. 7 is a diagram illustrating yet another extended example of themulti-path converter shown in FIG. 3 .

FIG. 8 is a diagram illustrating yet another extended example of themulti-path converter shown in FIG. 3 .

FIG. 9 is a diagram illustrating yet another extended example of themulti-path converter shown in FIG. 3 .

FIG. 10 is a diagram illustrating yet another extended example of themulti-path converter shown in FIG. 3 .

FIG. 11 is a flowchart illustrating a control method of the multi-pathconverter according to the exemplary embodiment.

FIG. 12 is a block diagram illustrating a first step-down converter witha dual-path according to an exemplary embodiment.

FIG. 13 is a circuit diagram illustrating a configuration of the firststep-down converter shown in FIG. 12 .

FIGS. 14A and 14B show diagrams for describing an example of a step-downoperation mode of the first step-down converter shown in FIG. 13 .

FIG. 15 shows diagrams illustrating an example of the first step-downconverter with the dual-path according to the exemplary embodiment.

FIG. 16 shows graphs each obtained by testing the first step-downconverter with the dual-path according to the exemplary embodiment in anenvironment with a duty ratio of 0.4.

FIG. 17 is a graph obtained by testing the first step-down converterwith the dual-path according to the exemplary embodiment in a firstsimulation environment.

FIG. 18 is a graph obtained by testing the first step-down converterwith the dual-path according to the exemplary embodiment in a secondsimulation environment.

FIG. 19 is a flowchart illustrating a control method of the firststep-down converter with the dual-path according to the exemplaryembodiment.

FIG. 20 is a flowchart illustrating a current transferring operationshown in FIG. 19 in more detail.

FIG. 21 is a circuit diagram illustrating a configuration of a secondstep-down converter with a dual-path according to the exemplaryembodiment.

FIGS. 22A to 22C show diagrams for describing an example of a step-downoperation mode of the second step-down converter shown in FIG. 21

FIG. 23 is a diagram illustrating an example of the second step-downconverter with the dual-path according to the exemplary embodiment.

FIG. 24 is a flowchart illustrating a control method of the secondstep-down converter with the dual-path according to the exemplaryembodiment.

FIG. 25 is a flowchart illustrating a current transferring operationshown in FIG. 24 in more detail.

FIG. 26 is a circuit diagram illustrating a configuration of a thirdstep-down converter with a dual-path according to the exemplaryembodiment.

FIGS. 27A and 27B show diagrams for describing an example of a step-downoperation mode of the third step-down converter shown in FIG. 26 .

FIG. 28 is a flowchart illustrating a control method of the thirdstep-down converter with the dual-path according to the exemplaryembodiment.

FIG. 29 is a circuit diagram illustrating a configuration of a fourthstep-down converter with a dual-path according to the exemplaryembodiment.

FIGS. 30A to 30B show diagrams for describing an example of a step-downoperation mode of the fourth step-down converter shown in FIG. 29 .

FIG. 31 is a circuit diagram illustrating a configuration of a fifthstep-down converter with a dual-path according to the exemplaryembodiment.

FIGS. 32A to 32C show diagrams for describing an example of a step-downoperation mode of the fifth step-down converter shown in FIG. 31 .

FIG. 33 is a circuit diagram illustrating a configuration of a sixthstep-down converter with a dual-path according to the exemplaryembodiment.

FIGS. 34A and 34B show diagrams for describing an example of a step-downoperation mode of the sixth step-down converter shown in FIG. 33 .

FIGS. 35A to 35C show diagrams for describing another example of astep-down operation mode of the sixth step-down converter shown in FIG.33 .

FIG. 36 is a circuit diagram illustrating a configuration of a seventhstep-down converter with a dual-path according to the exemplaryembodiment.

FIG. 37 is a circuit diagram illustrating a configuration of an eighthstep-down converter with a dual-path according to the exemplaryembodiment.

FIG. 38 is a circuit diagram illustrating a configuration of a ninthstep-down converter with a dual-path according to the exemplaryembodiment.

FIG. 39 is a circuit diagram illustrating a configuration of a tenthstep-down converter with a dual-path according to the exemplaryembodiment.

FIG. 40 is a circuit diagram illustrating a configuration of an eleventhstep-down converter with a triple-path according to the exemplaryembodiment.

FIG. 41 is a circuit diagram illustrating a configuration of a twelfthstep-down converter with a triple-path according to the exemplaryembodiment.

FIG. 42 is a circuit diagram illustrating a configuration of athirteenth step-down converter with a multi-path according to theexemplary embodiment.

FIG. 43 is a circuit diagram illustrating a configuration of afourteenth step-down converter with a multi-path according to theexemplary embodiment.

FIG. 44 is a block diagram illustrating a first step-up converter with adual-path according to another exemplary embodiment.

FIG. 45 is a circuit diagram illustrating a configuration of the firststep-up converter shown in FIG. 44 .

FIGS. 46A and 46B show diagrams for describing an example of a step-upoperation mode of the first step-up converter with the dual-pathaccording to another exemplary embodiment.

FIGS. 47A to 47C show diagrams for describing another example of astep-up operation mode of the first step-up converter with the dual-pathaccording to another exemplary embodiment.

FIGS. 48A and 48B show diagrams for describing inductor current changedue to step-up operation mode of first step-up converter havingdual-path according to another exemplary embodiment.

FIG. 49 shows graphs each obtained by testing the first step-upconverter according to another exemplary embodiment in an environmentwith a duty ratio of 0.5.

FIG. 50 shows graphs each obtained by testing the first step-upconverter according to another exemplary embodiment in an environmentwith a duty ratio of 0.7.

FIG. 51 shows graphs each obtained by testing the first step-upconverter according to another exemplary embodiment in an environmentwith a duty ratio of 0.4.

FIG. 52 shows graphs each obtained by testing the first step-upconverter according to another exemplary embodiment in an environmentwith a duty ratio of 0.2.

FIG. 53 is a flowchart illustrating a control method of the firststep-up converter with the dual-path according to another exemplaryembodiment.

FIG. 54 is a flowchart illustrating a stepped-up power transferringoperation shown in FIG. 53 in more detail.

FIG. 55 is a diagram illustrating an example of a configuration and astep-up operation mode of a second step-up converter with the dual-pathaccording to another exemplary embodiment.

FIG. 56 is a diagram illustrating another example of a step-up operationmode of the second step-up converter shown in FIG. 55 .

FIG. 57 is a circuit diagram illustrating a configuration of a thirdstep-up converter with a multi-path according to another exemplaryembodiment.

FIG. 58 is a circuit diagram illustrating a configuration of a fourthstep-up converter with a multi-path according to another exemplaryembodiment.

FIGS. 59A and 59B show diagrams for describing an example in which thesecond step-down converter shown in FIG. 21 is operated in a single-pathmanner.

FIG. 60 is a graph showing a comparison between efficiencies when thesecond step-down converter shown in FIG. 21 is operated in a multi-pathmanner and a single-path manner.

FIG. 61 is a flowchart for describing a step-down converting methodaccording to a first exemplary embodiment.

FIG. 62 is a graph showing a comparison between efficiencies when thesecond step-down converter shown in FIG. 21 is operated in a two-phasemanner and a three-phase manner.

FIG. 63 is a flowchart for describing a step-down converting methodaccording to a second exemplary embodiment.

MODES OF THE INVENTION

Hereinafter, exemplary embodiments of a converter with a multi-path anda control method thereof according to the exemplary embodiments will bedescribed in detail with reference to the accompanying drawings.

A multi-path converter and a control method thereof according to anexemplary embodiment will be described with reference to FIGS. 3 to 11 .

First, the multi-path converter according to the exemplary embodimentaccording to the present invention will be described with reference toFIG. 3 .

FIG. 3 is a block diagram illustrating the multi-path converteraccording to the exemplary embodiment.

Referring to FIG. 3 , in a converter 100 having multiple paths(hereinafter, referred to as a “converter”) according to the exemplaryembodiment, a current is divided and transferred to an output terminalthrough a plurality of parallel current transfer paths using inductorsand capacitors. That is, the converter 100 uses a current transfer pathusing a capacitor in addition to a current transfer path using aninductor, a current flows through a plurality of parallel paths so as tobe output to an output terminal (load), thereby reducing a total rootmean square (RMS) current flowing in the inductor.

To this end, the converter 100 may include an input unit 110 to whichpower is input, a conversion unit 130 which converts (steps down or up)a voltage of the input power, and an output unit 150 which receives andtransfers the converted power to an external device.

Here, the input unit 110 may include an alternating current (AC) powersource, a direct current (DC) power source, a power supply source(various voltage or current power sources), and the like.

In addition, the output unit 150 may include any type of load that maybe modeled using various passive elements including a resistor, acapacitor, and an inductor. That is, any type of load using aconventional power management integrated circuit (PMIC) may be includedin the output unit 150.

The conversion unit 130 may include functions of all conventionalconverters. For example, the conversion unit 130 may perform a functionof a step-down converter or buck converter in which a voltage of anoutput terminal is lower than a voltage of an input terminal. Also, theconversion unit 130 may perform a function of a step-up converter orboost converter in which a voltage of an output terminal is higher thana voltage of an input terminal. The conversion unit 130 may also performa function of a step-up-and-down converter or buck-boost converter inwhich a voltage of an output terminal is lower or higher than a voltageof an input terminal.

The conversion unit 130 divides and transfers a current to the outputunit through a plurality of current transfer paths. For example, theconversion unit 130 may divide and transfer a current to the output unit150 through the plurality of current transfer paths including a firstcurrent transfer path using an inductor and a second current transferpath using a capacitor. Here, in the plurality of current transferpaths, at least one of the first current transfer path and the secondcurrent transfer path may include a plurality of current transfer paths.For example, the plurality of current transfer paths may include acurrent transfer path using an inductor, a current transfer path using afirst capacitor, and a current transfer path using a second capacitor.Of course, one current transfer path may use one inductor, onecapacitor, a plurality of inductors, a plurality of capacitors, or acombination of at least one inductor and at least one capacitor.

In addition, when the conversion unit 130 repeatedly performs anoperation including a plurality of conversion operation modes (forexample, a plurality of step-down operation modes or a plurality ofstep-up operation modes), the conversion unit 130 may divide andtransfer a current to the output unit 150 through the plurality ofcurrent transfer paths in an entire section in which the plurality ofconversion operation modes are driven or in a partial section in whichsome conversion operation modes of the plurality of conversion operationmodes are driven.

As described above, in the converter 100 according to the exemplaryembodiment, a current may be divided and supplied to a load through anadditional parallel current transfer path using a capacitor unlike aconventional converter in which a current is supplied to a load by usingonly an inductor. That is, according to the converter 100, a DC currentlevel of an inductor may be reduced. When the converter 100 performs afunction of a step-down converter, a ripple current of an inductor maybe reduced. In addition, an inductor and a capacitor of the converter100 may supply a static current to the load (i.e., output terminal). Inaddition, as compared with an inductor, as can be confirmed in Table 1,a capacitor includes a much smaller parasitic resistor and has arelatively small volume and low unit cost. Therefore, as compared withonly using a plurality of inductors, adding a capacitor may reduce acurrent level flowing in an inductor. Thus, it is possible toconsiderably reduce power loss occurring in a parasitic resistor andovercome a limitation of power efficiency which is not overcome by anyconventional power management circuit technology. In addition, by usinga capacitor having a relatively small volume and low unit cost, it ispossible to reduce the volume and cost of inductor that is relativelylarge and expensive. Accordingly, it is possible to greatly reduce heatgenerated in a power management circuit, increase a usage time of adevice, and reduce consumption of an area and volume of a printedcircuit board (PCB).

TABLE 1 List of External Inductors Inductance (uH) Saturation currentrating (A) Dimension [L×W×H] (mm) DCR (mΩ) Cost($) @1000 Type Bulky sizeand small DCR 4.7 25.4 11.8×11.8×10.0 5.7 2.05 XAL1010-472 4.7 1213.0×13.0×6.0 6.1 0.74 SER1360-472 2.2 10 11.2×11.2×5.2 4.0 1.15SER1052-222 2.2 19.6 8.0×8.0×7.0 6.3 1.45 XAL7070-222 Small size, largeDCR, and cheap price 4.7 0.57 2.2×1.45×1.0 680 0.29 PFL2010-472 4.7 1.15.0×5.0×1.0 175 0.49 LPS5010-472 2.2 1.4 3.2×2.3×1.5 130 0.28PFL3515-222 2.2 2.7 5.0×5.0×1.5 90 0.46 LPS5015-222 2.2 0.792.2×1.45×/1.0 465 0.29 PFL2010-222 2.2 1.6 5.0×5.0×1.0 100 0.49LPS5010-222 List of External Capacitors Capacitance (uF) Rated Voltage[DC] (V) Dimension [L×W×H] (mm) ESR (mΩ) Cost($) @1000 Type Small size,small ESR, and cheap price 22 10 2.0×1.25×0.85 2.6 0.14C2012X5R1A226M085AC 22 10 2.0×1.25×1.25 2.3 0.16 C2012X5R1A226K125AB 1025 2.0×1.25×0.85 2.7 0.05 C2012X5R1C106K085AC 10 25 2.0×1.25×1.25 2.10.08 C2012X5R1E106K125AB 10 6.3 1.6×0.8×0.8 4.4 0.13 C1608X5R0J106K080AB

Extended examples of the multi-path converter according to the exemplaryembodiment will be described with reference to FIGS. 4 to 10 .

FIG. 4 is a diagram illustrating an example of the multi-path convertershown in FIG. 3 .

Referring to FIG. 4 , a converter 100 according to the exemplaryembodiment may include one conversion unit 130, one output unit 150, anda plurality of input units 110. Here, an output voltage may have variouscharacteristics such as step-down, step-up, and step-down-and-up.

A plurality of inductors, a plurality of capacitors, and/or a pluralityof switches may be included in the conversion unit 130. Here, examplesof the input unit 110 may include, but are not limited to, an AC powersource, a DC power source, a power supply source (various voltage orcurrent power sources), and the like. In addition, the output unit 150may include any type of load that may be modeled using various passiveelements including a resistor, a capacitor, and an inductor, that is,any type of load using the conventional PMIC.

FIG. 5 is a diagram illustrating another example of the multi-pathconverter shown in FIG. 3 .

Referring to FIG. 5 , a converter 100 according to the exemplaryembodiment may include one input unit 110, one conversion unit 130, anda plurality of output units 150.

Here, an output voltage may have various characteristics such asstep-down, step-up, and step-down-and-up.

A plurality of inductors, a plurality of capacitors, and/or a pluralityof switches may be included in the conversion unit 130. In addition,examples of the input unit 110 may include, but are not limited to, anAC power source, a DC power source, a power supply source (variousvoltage or current power sources), and the like. Furthermore, the outputunit 150 may include any type of load that may be modeled using variouspassive elements including a resistor, a capacitor, and an inductor.That is, any type of load using the conventional PMIC may be included inthe output unit 150.

FIG. 6 is a diagram illustrating still another example of the multi-pathconverter shown in FIG. 3 .

Referring to FIG. 6 , a converter 100 according to the exemplaryembodiment may include a plurality of input units 110, a plurality ofconversion units 130, and a plurality of output units 150.

Here, an output voltage may have various characteristics such asstep-down, step-up, and step-down-and-up.

A plurality of inductors, a plurality of capacitors, and/or a pluralityof switches may be included in the conversion unit 130. In addition, theinput unit 110 may include an AC power source, a DC power source, apower supply source (various voltage or current power sources), and thelike. Furthermore, the output unit 150 may include any type of load thatmay be modeled using various passive elements including a resistor, acapacitor, and an inductor. That is, any type of load using theconventional PMIC may be included in the output unit 150.

FIG. 7 is a diagram illustrating yet another example of the multi-pathconverter shown in FIG. 3 .

Referring to FIG. 7 , a converter 100 according to the exemplaryembodiment may include one input unit 110, one output unit 150, and aplurality of conversion units 130.

Here, the plurality of conversion units 130 may be connected in serieswith each other.

FIG. 8 is a diagram illustrating yet another example of the multi-pathconverter shown in FIG. 3 .

Referring to FIG. 8 , a converter 100 according to the exemplaryembodiment may include one input unit 110, one output unit 150, and aplurality of conversion units 130.

Here, the plurality of conversion units 130 may be connected in parallelwith each other.

The conversion units 130 are arranged in parallel in FIG. 7 and arrangedin parallel in FIG. 8 , but the arrangement of the conversion units 130is not limited thereto. For example, the plurality of conversion units130 may be connected in series-parallel (combination of series andparallel) with each other according to exemplary embodiments.

FIG. 9 is a diagram illustrating yet another example of the multi-pathconverter shown in FIG. 3 .

Referring to FIG. 9 , a converter 100 according to the exemplaryembodiment may include one input unit 110, one output unit 150, aplurality of conversion units 130, and a conventional converter module10.

Here, the plurality of conversion units 130 and the conventionalconverter module 10 may be connected in series with each other.

FIG. 10 is a diagram illustrating yet another example of the multi-pathconverter shown in FIG. 3 .

Referring to FIG. 10 , a converter 100 according to the exemplaryembodiment may include one input unit 110, one output unit 150, aplurality of conversion units 130, and a conventional converter module10.

Here, the plurality of conversion units 130 and the conventionalconverter module 10 may be connected in parallel with each other.

The plurality of conversion units 130 and the conventional convertermodule 10 are connected in serial in FIG. 9 and connected in parallel inFIG. 10 , the arrangement is not limited thereto. For example, theplurality of conversion units 130 and the conventional converter module10 may be connected in series-parallel (combination of series andparallel) with each other according to exemplary embodiments.

In addition, in the converter 100 shown in FIGS. 7 to 10 , the pluralityof conversion units 130 may be operated in synchronization with eachother. Otherwise, the plurality of conversion units 130 may beindependently operated according to different clocks.

The control method of the multi-path converter according to theexemplary embodiment will be described with reference to FIG. 11 .

FIG. 11 is a flowchart illustrating the control method of the multi-pathconverter according to the exemplary embodiment.

Referring to FIG. 11 , the control method of the multi-path converteraccording to the exemplary embodiment includes converting (e.g.,stepping down or up) a voltage of power input to the converter 10 andtransferring a current to the output terminal. The current is dividedand transferred to the output terminal through a plurality of currenttransfer paths using at least one inductor and at least one capacitor(S100).

In this case, in the transferring of the current, the current is dividedand transferred to the output unit through the plurality of currenttransfer paths. For example, in the converter 100, the current may bedivided and transferred to the output terminal through the plurality ofcurrent transfer paths including a first current transfer path using aninductor and a second current transfer path using a capacitor. Here, theplurality of current transfer paths may include a plurality of the firstcurrent transfer paths and/or a plurality of the second current transferpaths. For example, the plurality of current transfer paths may includea current transfer path using an inductor, a current transfer path usinga first capacitor, and a current transfer path using a second capacitor.According to an exemplary embodiment, one current transfer path may useone or more inductors, one or more capacitors, or a combination thereof.

In addition, in the transferring of the current, when an operationincluding a plurality of conversion operation modes (for example, aplurality of step-down operation modes or a plurality of step-upoperation modes) is periodically performed, the current may be dividedand transferred to the output terminal through the plurality of currenttransfer paths in an entire section in which the plurality of conversionoperation modes are driven or in a partial section in which someconversion operation modes of the plurality of conversion operationmodes are driven.

As described above, in the multi-path converter and the control methodthereof according to the exemplary embodiments, a current is divided andtransferred through a plurality of current transfer paths using at leastone inductor and at least one capacitor to flow to an output terminal(i.e., a load). As such, an amount of power loss may be reduced ascompared with a conventional converter, thereby increasing powerefficiency.

Embodiment 1: Multi-Path Step-Down Converter

A multi-path converter and a control method thereof according toexemplary embodiments will be described in detail with reference toFIGS. 12 and 43 .

The multi-path converter according to the exemplary embodiment mayperform a function of a step-down converter configured to step downinput power. That is, in the converter according to the exemplaryembodiment, an output voltage V_(OUT) is lower than an input voltageV_(IN), and a current is divided and transferred to an output terminalthrough a plurality of current transfer paths (for example, two currenttransfer paths, three current transfer paths, or n current transferpaths) using at least one inductor and at least one capacitor.

First, a first step-down converter with a dual-path according to theexemplary embodiment will be described with reference to FIGS. 12 to 14.

FIG. 12 is a block diagram illustrating the first step-down converterwith the dual-path according to the exemplary embodiment. FIG. 13 is acircuit diagram illustrating a configuration of the first step-downconverter shown in FIG. 12 . FIGS. 14A and 14B show diagrams fordescribing an example of a step-down operation mode of the firststep-down converter shown in FIG. 13 .

Referring to FIGS. 12 and 13 , a first step-down converter 100-1 with adual-path (hereinafter, referred to as a “first step-down converter”)according to the exemplary embodiment includes an input unit 110 towhich power is input, a conversion unit 130 which steps down the inputpower, and an output unit 150 which receives and transfers thestepped-down power to an external device. Here, a power conversion ratio(V_(OUT)/V_(IN)) of the first step-down converter 100-1 is in a range of0.5 to 1.

That is, the conversion unit 130 steps down the power input through theinput unit 110 and transfers the stepped-down power to the output unit150. The conversion unit 130 transfers a current to the output unit 150through two different current transfer paths. For example, theconversion unit 130 may divide and transfer the current to the outputunit 150 through a first current transfer path using an inductor I and asecond current transfer path using a capacitor C. Accordingly, ascompared with a conventional step-down converter which transfers acurrent to an output terminal (i.e., load) only through an inductor, thefirst step-down converter 100 according to the exemplary embodimentdivides and transfers the current to the output terminal through thefirst current transfer path including the inductor I and the secondcurrent transfer path including the capacitor C. As such, power loss isreduced and efficiency is increased.

To this end, the conversion unit 130 may include the inductor I, thecapacitor C, a first switch SW1, a second switch SW2, and a third switchSW3.

One end of the inductor I is connected to a node between the firstswitch SW1 and the capacitor C, and the other end thereof is connectedto a node between the output unit 150 and the second switch SW2.

One end of the capacitor C is connected to a node between the firstswitch SW1 and the inductor I, and the other end thereof is connected toa node between the second switch SW2 and the third switch SW3.

One end of the first switch SW1 is connected to the input unit 110, andthe other end thereof is connected to a node between the inductor I andthe capacitor C.

One end of the second switch SW2 is connected to a node between thecapacitor C and the third switch SW3, and the other end thereof isconnected to a node between the inductor I and the output unit 150.

One end of the third switch SW3 is connected to a node between thecapacitor C and the second switch SW2, and the other end thereof isconnected to a node between the input unit 110 and the output unit 150.

More specifically, the conversion unit 130 may be driven in the order ofa first step-down operation mode and a second step-down operation mode.That is, the conversion unit 130 may periodically perform an operationthat sequentially includes the first step-down operation mode and thesecond step-down operation mode. The conversion unit 130 may step downthe power input from the input unit 110, and transfer the stepped-downpower to the output unit 150. In this case, a duty ratio indicating adriving time of the first step-down operation mode may be determinedbased on an input voltage, an output voltage, and the like.

As shown in FIG. 14A, the conversion unit 130 may be driven in the firststep-down operation mode in which the first switch SW1 and the secondswitch SW2 are turned on and the third switch SW3 is turned off.Accordingly, a current flowing to the output unit 150 (i.e., a load) isdivided and transferred through a first current transfer path P1composed of the inductor I and a second current transfer path P2composed of the capacitor C. Therefore, an RMS value of the currentflowing in the inductor I is reduced due to the additional currenttransfer path using the capacitor C.

After the conversion unit 130 is driven in the first step-down operationmode, the conversion unit 130 may be driven in the second step-downoperation mode in which the third switch SW3 is turned on and the firstswitch SW1 and the second switch SW2 are turned off, as shown in FIG.14B.

As described above, in the first step-down operation mode, while acurrent is accumulated in the inductor I, a current is divided andtransferred to the output unit 150 (i.e., the load) through the firstcurrent transfer path using the inductor I and the second currenttransfer path using the capacitor C. In the second step-down operationmode, the current accumulated in the inductor I is transferred to theoutput unit 150, that is, the load. Accordingly, since a current to betransferred to the output unit 150 (i.e., the load) is divided andtransferred through two paths (first current transfer path and secondcurrent transfer path), an amount of power loss of the first step-downconverter 100-1 according to the exemplary embodiment may be furtherreduced as compared with the conventional step-down converter, therebyincreasing power efficiency.

The first step-down converter according to the exemplary embodiment willbe further described with reference to FIGS. 15 and 16 .

FIG. 15 shows diagrams illustrating an example of the first step-downconverter according to the exemplary embodiment, and FIG. 16 showsgraphs each obtained by testing the first step-down converter accordingto the exemplary embodiment in an environment with a duty ratio of 0.4.That is, FIG. 16 illustrates waveforms obtained by testing the firststep-down converter 100-1 according to the exemplary embodiment underconditions in which a duty ratio is 40%, a voltage V_(IN) input throughthe input unit 110 is 5 V, a voltage V_(OUT) output through the outputunit 150 is 3.06 V, and a current output through the output unit 150 is1 A.

Referring to FIGS. 15 and 16 , the first step-down converter 100-1according to the exemplary embodiment periodically performs an operationthat sequentially includes a first step-down operation mode Φ₁ and asecond step-down operation mode Φ₂ to step down and transfer input powerto the output terminal, that is, the load.

In this case, when the first step-down converter 100-1 according to theexemplary embodiment is driven in the first step-down operation mode Φ₁,in the first step-down converter 100-1, a current is divided andtransferred to the output terminal (i.e., the load) through the firstcurrent transfer path using the inductor I and the second currenttransfer path using the capacitor C.

Performance of the first step-down converter according to the exemplaryembodiment will be further described with respect to FIGS. 17 and 18 .

FIG. 17 is a graph obtained by testing the first step-down converterwith the dual-path according to the exemplary embodiment in a firstsimulation environment, and FIG. 18 is a graph obtained by testing thefirst step-down converter with the dual-path according to the exemplaryembodiment in a second simulation environment.

In order to test the performance of the first step-down converter 100-1according to the exemplary embodiment, experiments were performed so asto compare the first step-down converter 100-1 with the conventionalstep-down converter in two simulation environments.

In the first simulation environment, the input voltage V_(IN) was fixedat 4.5 V, a driving time D₁ of the first step-down operation mode waschanged between 0.05 and 0.95, and the current of the output terminal(that is, the load) was fixed at 1 A. Accordingly, the voltage V_(OUT)of the output terminal (that is, the load) is V_(IN)/(2-D₁), that is,2.25 V<V_(OUT)<4.5 V, and a driving time D₂ of the second step-downoperation mode is ⅟(2-D₁).

In the second simulation environment, the voltage V_(OUT) of the outputterminal (that is, the load) was fixed at 2.8 V, the driving time D₁ ofthe first step-down operation mode was changed between 0.05 and 0.95,and the current of the output terminal (that is, the load) was fixed at1 A. Accordingly, the input voltage V_(IN) is V_(OUT)(2-D₁), that is,3.0 V<V_(IN)<5.5 V, and the driving time D₂ of the second step-downoperation mode is ⅟(2-D₁).

Referring to FIG. 17 , a test result in the first simulation environmentconfirms that power efficiency (solid line in FIG. 17 ) of the firststep-down converter according to the exemplary embodiment is increasedby about 5% as compared with power efficiency (dashed line in FIG. 17 )of the conventional step-down converter.

Referring to FIG. 18 , as a test result in the second simulationenvironment, it may be confirmed that power efficiency (solid line inFIG. 18 ) of the first step-down converter according to the exemplaryembodiment is further increased by about 4.7% as compared with powerefficiency (dashed line in FIG. 18 ) of the conventional step-downconverter.

A control method of the first step-down converter according to theexemplary embodiment will be described with reference to FIGS. 19 and 20.

FIG. 19 is a flowchart illustrating the control method of the firststep-down converter according to the exemplary embodiment.

Referring to FIG. 19 , the first step-down converter 100-1 steps down aninput power to transfer a current to the output unit 150, and when thecurrent is transferred to the output unit 150, the current istransferred to the output unit 150 through two different currenttransfer paths (S110-1).

For example, in the first step-down converter 100-1, the current may bedivided and transferred to the output unit 150 through a first currenttransfer path using the inductor I and a second current transfer pathusing the capacitor C. Accordingly, as compared with the conventionalstep-down converter which transfers a current to the output terminal(i.e., load) only through an inductor, the first step-down converter100-1 according to the exemplary embodiment divides and transfers thecurrent to the output terminal through the first current transfer pathincluding the inductor I and the second current transfer path includingthe capacitor C, thereby reducing power loss and increasing efficiency.

FIG. 20 is a flowchart illustrating a current transferring operationshown in FIG. 19 in more detail.

Referring to FIG. 20 , the first step-down converter 100-1 may be drivenin a first step-down operation mode (S111). That is, the first step-downconverter 100-1 may be driven in the first step-down operation mode inwhich the first switch SW1 and a second switch SW2 are turned on and thethird switch SW3 is turned off. Accordingly, a current which flows tothe output unit 150 (i.e., the load) is divided and transferred througha first current transfer path P1 using the inductor I and a secondcurrent transfer path P2 using the capacitor C.

After the first step-down converter 100-1 is driven in the firststep-down operation mode, the first step-down converter 100-1 may bedriven in a second step-down operation mode (S113). In the secondstep-down operation mode, the third switch SW3 is turned on and thefirst switch SW1 and the second switch SW2 are turned off.

As described above, the first step-down converter 100-1 may periodicallyperform an operation that sequentially includes the first step-downoperation mode and the second step-down operation mode. As such, thefirst step-down converter 100-1 may step down and transfer the powerinput from the input unit 110 to the output unit 150.

In the first step-down operation mode, while a current is accumulated inthe inductor I, a current is divided and transferred to the output unit150 (i.e., the load) through the first current transfer path using theinductor I and the second current transfer path using the capacitor C.In the second step-down operation mode, the current accumulated in theinductor I is transferred to the output unit 150, that is, the load.Accordingly, since the current to be transferred to the output unit 150(i.e., the load) is divided and transferred through two paths (firstcurrent transfer path and second current transfer path), an amount ofpower loss of the first step-down converter 100-1 according to theexemplary embodiment may be reduced as compared with the conventionalstep-down converter, thereby increasing power efficiency.

A second step-down converter with a dual-path according to the exemplaryembodiment will be described with reference to FIGS. 21 to 22 .

FIG. 21 is a circuit diagram illustrating a configuration of the secondstep-down converter with the dual-path according to the exemplaryembodiment. FIGS. 22A to 22C show diagrams for describing an example ofa step-down operation mode of the second step-down converter shown inFIG. 21 .

Since a second step-down converter 200-1 with a dual-path (hereinafterreferred to as a “second step-down converter”) according to theexemplary embodiment is substantially similar to the first step-downconverter 100-1 according to the above-described exemplary embodiment,differences therebetween will be described.

Referring to FIG. 21 , the second step-down converter 200-1 according tothe exemplary embodiment further includes a fourth switch SW4 added tothe first step-down converter 100-1 according to the exemplaryembodiment.

That is, a conversion unit 230 may include an inductor I, a capacitor C,a first switch SW1, a second switch SW2, a third switch SW3, and thefourth switch SW4.

One end of the fourth switch SW4 is connected to a node between thefirst switch SW1 and the inductor I, and the other end thereof isconnected to a node between the input unit 110 and the third switch SW3.

Here, the first switch SW1 may be a P-type metal oxide semiconductor(PMOS) switch. The second switch SW2, the third switch SW3, and thefourth switch SW4 may be N-type metal oxide semiconductor (NMOS)switches.

More specifically, the conversion unit 230 may be driven in the order ofa first step-down operation mode, a third step-down operation mode, anda second step-down operation mode. That is, the conversion unit 230 mayperiodically perform an operation that sequentially includes the firststep-down operation mode, the third step-down operation mode, and thesecond step-down operation mode. As such, the conversion unit 230 maystep down and transfer power input from an input unit 210 to an outputunit 250.

That is, as shown in FIG. 22A, the conversion unit 230 may be driven inthe first step-down operation mode in which the first switch SW1 and thesecond switch SW2 are turned on and the third switch SW3 and the fourthswitch SW4 are turned off. Accordingly, a current which flows to theoutput unit 250 (i.e., a load) is divided and transferred through afirst current transfer path P1 using an inductor I and a second currenttransfer path P2 using a capacitor C. Therefore, an RMS value of thecurrent flowing in the inductor I is reduced due to the additionalcurrent transfer path using the capacitor C.

After the conversion unit 230 is driven in the first step-down operationmode, as shown in FIG. 22B, the conversion unit 230 may be driven inthird step-down operation mode in which the fourth switch SW4 is turnedon and the first switch SW1, the second switch SW2, and the third switchSW3 are turned off.

In addition, after the conversion unit 230 is driven in the thirdstep-down operation mode, as shown in FIG. 22C, the conversion unit 230may be driven in the second step-down operation mode in which the thirdswitch SW3 is turned on and the first switch SW1, the second switch SW2,and the fourth switch SW4 are turned off.

As described above, in the first step-down operation mode, while acurrent is accumulated in the inductor I, a current is divided andtransferred to the output unit 250 (i.e., the load) through the firstcurrent transfer path using the inductor I and the second currenttransfer path using the capacitor C. Accordingly, since a current to betransferred to the output unit 250 (i.e., the load) is divided andtransferred through two paths (first current transfer path and secondcurrent transfer path), an amount of power loss of the second step-downconverter 200-1 according to the exemplary embodiment may be reduced ascompared with the conventional step-down converter, thereby increasingpower efficiency.

In addition, unlike the first step-down converter 100-1, the secondstep-down converter 200-1 includes the fourth switch SW4 which enablesthe third step-down operation mode. Thus, the second step-down converter200-1 has a power conversion ratio (V_(OUT)/V_(IN)) ranging from 0 and1, which is a range wider than that of the first step-down converter100-1. Furthermore, in the second step-down converter 200-1, an RMScurrent flowing in the first switch SW1 may be reduced as compared withthe first step-down converter 100-1. Also, an RMS current flowing in thecapacitor C may be reduced by adjusting a duty ratio of the firststep-down operation mode Φ₁ and the second step-down operation mode Φ₃.

That is, the first step-down converter 100-1 according to the exemplaryembodiment may provide an output voltage having a range represented by[Expression 1] below.

$\begin{matrix}{\text{V}_{\text{OUT}} = {1/{\left( \text{2 - D}_{1} \right)*\text{V}_{\text{IN}}}}} & \text{­­­[Expression 1]}\end{matrix}$

(1/2 * V_(IN) ≤ V_(OUT) ≤ V_(IN))

Here, V_(IN) refers to an input voltage, V_(OUT) refers to an outputvoltage, and D₁ refers to a driving time of the first step-downoperation mode.

On the other hand, the second step-down converter 200-1 according to theexemplary embodiment may provide an output voltage having a rangerepresented by [Expression 2] below.

$\begin{matrix}{\text{V}_{\text{OUT}} = {\left( {1\text{- D}_{\text{2}}} \right)/\left( {2\text{- D}_{1}\text{- D}_{2}} \right)}*\text{V}_{\text{IN}}} & \text{­­­[Expression 2]}\end{matrix}$

(0 ≤ V_(OUT) ≤ V_(IN))

Here, V_(IN) refers to an input voltage, V_(OUT) refers to an outputvoltage, D₁ refers to a driving time of the first step-down operationmode, and D₂ refers to a driving time of the third step-down operationmode.

An example of the second step-down converter according to the exemplaryembodiment will be described with reference to FIG. 23 .

FIG. 23 is a diagram illustrating an example of the second step-downconverter according to the exemplary embodiment.

Referring to FIG. 23 , the second step-down converter 200-1 according tothe exemplary embodiment repeatedly performs an operation including afirst step-down operation mode Φ₁, a third step-down operation mode Φ₂,and a second step-down operation mode Φ₃ and steps down and transfersinput power to an output terminal, i.e., a load.

In this case, when the second step-down converter 200-1 according to theexemplary embodiment is driven in the first step-down operation mode Φ₁,in the first step-down converter 100-1, a current is divided andtransferred to the output terminal (i.e., the load) through the firstcurrent transfer path using the inductor I and the second currenttransfer path using the capacitor C.

A control method of the second step-down converter according to theexemplary embodiment will be described with reference to FIGS. 24 and 25.

FIG. 24 is a flowchart illustrating the control method of the secondstep-down converter according to the exemplary embodiment.

Referring to FIG. 24 , the second step-down converter 200-1 steps downinput power to transfer a current to the output unit 250, and when thecurrent is transferred to the output unit 250, the current istransferred to the output unit 250 through two different currenttransfer paths (S210-1).

For example, in the second step-down converter 200-1, the current may bedivided and transferred to the output unit 250 through the first currenttransfer path using the inductor I and the second current transfer pathusing the capacitor C. Accordingly, as compared with the conventionalstep-down converter which transfers a current to an output terminal(i.e., load) through only an inductor, the second step-down converter200-1 according to the exemplary embodiment divides and transfers acurrent to an output terminal through the first current transfer pathpassing including the inductor I and the second current transfer pathincluding the capacitor C, thereby reducing power loss and increasingefficiency.

FIG. 25 is a flowchart illustrating a current transferring operationshown in FIG. 24 in more detail.

Referring to FIG. 25 , the second step-down converter 200-1 may bedriven in the first step-down operation mode (S211). That is, the secondstep-down converter 200-1 may be driven in the first step-down operationmode of turning the first switch SW1 and the second switch SW2 on andturning the third switch SW3 and the fourth switch SW4 off. Accordingly,a current flowing to the output unit 250 (i.e., the load) is divided andtransferred through the first current transfer path P1 using theinductor I and the second current transfer path P2 using the capacitorC.

After the second step-down converter 200-1 is driven in the firststep-down operation mode, the second step-down converter 200-1 may bedriven in the third step-down operation mode (S213) in which the fourthswitch SW4 is turned on and the first switch SW1, the second switch SW2,and the third switch SW3 are turned off.

After the second step-down converter 200-1 is driven in the thirdstep-down operation mode, the second step-down converter 200-1 may bedriven in the second step-down operation mode (S215) in which the thirdswitch SW4 is turned on and the first switch SW1, the second switch SW2,and the fourth switch SW4 are turned off.

As described above, the second step-down converter 200-1 mayperiodically perform an operation that sequentially includes the firststep-down operation mode, the third step-down operation mode, and thesecond step-down operation mode. As such, the second step-down converter200-1 may step down and transfer the power input from the input unit 210to the output unit 250.

That is, in the first step-down operation mode, while a current isaccumulated in the inductor I, a current is divided and transferred tothe output unit 250 (i.e., the load) through the first current transferpath using the inductor I and the second current transfer path using thecapacitor C. Accordingly, since the current to be transferred to theoutput unit 250 (i.e., the load) is divided and transferred through twopaths (first current transfer path and second current transfer path), anamount of power loss of the first step-down converter 200-1 according tothe exemplary embodiment may be reduced as compared with theconventional step-down converter, thereby increasing power efficiency.

A third step-down converter with a dual-path according to the exemplaryembodiment will be described with reference to FIGS. 26 to 27 .

FIG. 26 is a circuit diagram illustrating a configuration of the thirdstep-down converter with the dual-path according to the exemplaryembodiment. FIGS. 27A and 27B show diagrams for describing an example ofa step-down operation mode of the third step-down converter shown inFIG. 26 .

Since a third step-down converter 300-1 with a dual-path (hereinafterreferred to as a “third step-down converter”) according to the exemplaryembodiment is substantially similar to the second step-down converter200-1 according to the above-described exemplary embodiment, differencestherebetween will be described.

Referring to FIG. 26 , the third step-down converter 300-1 according tothe exemplary embodiment additionally includes a fifth switch SW5, asixth switch SW6, and a capacitor C2, in comparison with the secondstep-down converter 200-1.

That is, a conversion unit 330 may include an inductor I, a capacitor C,a first switch SW1, a second switch SW2, a third switch SW3, a fourthswitch SW4, a fifth switch SW5, a sixth switch SW6, and a capacitor C2.

One end of the capacitor C2 is connected to a node between the firstswitch SW1 and the inductor I, and the other end thereof is connected tothe fourth switch SW4.

One end of the sixth switch SW6 is connected to a node between thecapacitor C2 and the inductor I, and the other end thereof is connectedto the capacitor C.

One end of the fifth switch SW5 is connected to a node between thecapacitor C2 and the fourth switch SW4, and the other end thereof isconnected to a node between the sixth switch SW6 and the capacitor C.

More specifically, the conversion unit 330 may be driven in the order ofa first step-down operation mode and a second step-down operation mode.That is, the conversion unit 330 may periodically perform an operationthat sequentially includes the first step-down operation mode and thesecond step-down operation mode. As such, the conversion unit 330 maystep down and transfer power input from an input unit 310 to an outputunit 350.

That is, as shown in FIG. 27A, the conversion unit 330 may be driven inthe first step-down operation mode in which the first switch SW1, thesecond switch SW2, and the fifth switch SW5 are turned on and the thirdswitch SW3, the fourth switch SW4, and the sixth switch SW6 are turnedoff. Accordingly, a current which flows to the output unit 350 (i.e., aload) is divided and transferred through a first current transfer pathP1 using the inductor I and a second current transfer path P2 using thecapacitor C2 and the capacitor C.

After the conversion unit 330 is driven in the first step-down operationmode, the conversion unit 330 may be driven in the second step-downoperation mode in which the third switch SW3, the fourth switch SW4, andthe sixth switch SW6 are turned on and the first switch SW1, the secondswitch SW2, and the fifth switch SW5 are turned off, as shown in FIG.27B. Accordingly, the current flowing to the output unit 350 (i.e., theload) is divided and transferred through a third current transfer pathP3 using the capacitor C and a fourth current transfer path P4 using thecapacitor C2.

As described above, in the first step-down operation mode, a current isdivided and transferred to the output unit 350 (i.e., the load) throughthe first current transfer path P1 using the inductor I and the secondcurrent transfer path P2 using the capacitor C2 and the capacitor C. Inthe second step-down operation mode, a current is divided to the outputunit 350 (i.e., the load) through a third current transfer path P3 usingthe capacitor C and a fourth current transfer path using the capacitorC2. Accordingly, since the current is divided and transferred through aplurality of current transfer paths in an entire section in which aplurality of step-down operation modes are driven, an amount of powerloss of the third step-down converter 300-1 according to the exemplaryembodiment may be reduced as compared with the conventional step-downconverter, thereby increasing power efficiency.

A control method of the third step-down converter according to theexemplary embodiment will be described with reference to FIG. 28 .

FIG. 28 is a flowchart illustrating the control method of the thirdstep-down converter with the dual-path according to the exemplaryembodiment.

Referring to FIG. 28 , the third step-down converter 300-1 steps down aninput power to transfer a current to the output unit 350 through twodifferent current transfer paths (S310-1).

More specifically, the third step-down converter 300-1 may be driven inthe first step-down operation mode in which the first switch SW1, thesecond switch SW2, and the fifth switch SW5 are turned on and the thirdswitch SW3, the fourth switch SW4, and the sixth switch SW6 are turnedoff. Accordingly, a current flowing to the output unit 350 (i.e., theload) is divided and transferred through the first current transfer pathP1 using the inductor I and the second current transfer path P2 usingthe capacitor C2 and the capacitor C.

After the third step-down converter 300-1 is driven in the firststep-down operation mode, the third step-down converter 300-1 may bedriven in the second step-down operation mode in which the third switchSW3, the fourth switch SW4, and the sixth switch SW6 are turned on andthe first switch SW1, the second switch SW2, and the fifth switch SW5are turned off. Accordingly, a current flowing to the output unit 350(i.e., the load) is divided and transferred through the third currenttransfer path P3 using the capacitor C and the fourth current transferpath P4 using the capacitor C2.

A fourth step-down converter with a dual-path according to the exemplaryembodiment will be described with reference to FIGS. 29 and 30 .

FIG. 29 is a circuit diagram illustrating a configuration of the fourthstep-down converter with the dual-path according to the exemplaryembodiment, and FIGS. 30A and 30B show diagrams for describing anexample of a step-down operation mode of the fourth step-down convertershown in FIG. 29 .

Referring to FIG. 29 , a fourth step-down converter 400-1 with adual-path (hereinafter referred to as a “fourth step-down converter”)according to the present exemplary embodiment is configured by changingpositions of some elements of the first step-down converter 100-1. Here,a power conversion ratio (V_(OUT)/V_(IN)) of the fourth step-downconverter 400-1 is in the range of 0 to 0.5.

That is, a conversion unit 430 may include an inductor I, a capacitor C,a first switch SW1, a second switch SW2, and a third switch SW3.

One end of the inductor I is connected to a node between the capacitor Cand the third switch SW3, and the other end thereof is connected to anode between the second switch SW2 and an output unit 450.

One end of the capacitor C is connected to a node between the firstswitch SW1 and the second switch SW2, and the other end thereof isconnected to a node between the inductor I and the third switch SW3.

One end of the first switch SW1 is connected to an input unit 410, andthe other end thereof is connected to a node between the second switchSW2 and the capacitor C.

One end of the second switch SW2 is connected to a node between thefirst switch SW1 and the capacitor C, and the other end thereof isconnected to a node between the output unit 450 and the inductor I.

One end of the third switch SW3 is connected to a node between thecapacitor C and the inductor I, and the other end thereof is connectedto a node between the input unit 410 and the output unit 450.

More specifically, the conversion unit 430 may be driven in the order ofa first step-down operation mode and a second step-down operation mode.That is, the conversion unit 430 may periodically perform an operationthat sequentially includes the first step-down operation mode and thesecond step-down operation mode. As such, the conversion unit 430 maystep down and transfer power input from the input unit 410 to the outputunit 450.

That is, as shown in FIG. 30A, the conversion unit 430 may be driven inthe first step-down operation mode in which the first switch SW1 isturned on and the second switch SW2 and the third switch SW3 are turnedoff.

After the conversion unit 430 is driven in the first step-down operationmode, the conversion unit 430 may be driven in the second step-downoperation mode in which the second switch SW2 and the third switch SW3are turned on and the first switch SW1 is turned off, as shown in FIG.30B. Accordingly, a current which flows to the output unit 450 (i.e., aload) is divided and transferred through a first current transfer pathP1 using the inductor I and a second current transfer path P2 using thecapacitor C. Therefore, an RMS value of the current flowing in theinductor I is reduced due to the additional current transfer path usingthe capacitor C.

A fifth step-down converter with a dual-path according to the exemplaryembodiment will be described with reference to FIGS. 31 and 32 .

FIG. 31 is a circuit diagram illustrating a configuration of the fifthstep-down converter with the dual-path according to the exemplaryembodiment, and FIGS. 32A to 32C show diagrams for describing an exampleof a step-down operation mode of the fifth step-down converter shown inFIG. 31 .

Since a fifth step-down converter 500-1 with a dual-path (hereinafterreferred to as a “fifth step-down converter”) according to the exemplaryembodiment is substantially similar to the fourth step-down converter400-1 according to the above-described exemplary embodiment, differencestherebetween will be described.

Referring to FIG. 31 , the fifth step-down converter 500-1 according tothe exemplary embodiment may further include a fourth switch SW4 incomparison with the fourth step-down converter 400-1 .

That is, a conversion unit 530 may include an inductor I, a capacitor C,a first switch SW1, a second switch SW2, a third switch SW3, and afourth switch SW4.

One end of the inductor I is connected to a node between the capacitor Cand the third switch SW3, and the other end thereof is connected to anode between the second switch SW2 and an output unit 550.

One end of the fourth switch SW4 is connected to an input unit 510, andthe other end thereof is connected to a node between the capacitor C andthe third switch SW3.

More specifically, the conversion unit 530 may be driven in the order ofa first step-down operation mode, a third step-down operation mode, anda second step-down operation mode. That is, the conversion unit 530 mayperiodically perform an operation that sequentially includes the firststep-down operation mode, the third step-down operation mode, and thesecond step-down operation mode. As such, the conversion unit 530 maystep down and transfer power input from the input unit 510 to the outputunit 550.

That is, as shown in FIG. 32A, the conversion unit 530 may be driven inthe first step-down operation mode in which the first switch SW1 isturned on and the second switch SW2, the third switch SW3, and thefourth switch SW4 are turned off.

After the conversion unit 530 is driven in the first step-down operationmode, the conversion unit 530 may be driven in the third step-downoperation mode in which the fourth switch SW4 is turned on and the firstswitch SW1, the second switch SW2, and the third switch SW3 are turnedoff, as shown in FIG. 32B.

In addition, after the conversion unit 530 is driven in the thirdstep-down operation mode, the conversion unit 530 may be driven in thesecond step-down operation mode in which the second switch SW2 and thethird switch SW3 are turned on and the first switch SW1 and the fourthswitch SW4 are turned off, as shown in FIG. 32C. Accordingly, a currentwhich flows to the output unit 550 (i.e., a load) is divided andtransferred through a first current transfer path P1 using the inductorI and a second current transfer path P2 using the capacitor C.Therefore, an RMS value of the current flowing in the inductor I isreduced due to the additional current transfer path using the capacitorC.

As described above, since the current to be transferred to the outputunit 550 (i.e., the load) is divided and transferred through two paths(first current transfer path and second current transfer path), anamount of power loss of the fifth step-down converter 500-1 according tothe exemplary embodiment may be reduced as compared with theconventional step-down converter, thereby increasing power efficiency.

In addition, unlike the fourth step-down converter 400-1, the fifthstep-down converter 500-1 includes the fourth switch SW4 which enablesthe third step-down operation mode. As such, the fifth step-downconverter 500-1 has a power conversion ratio (V_(OUT)/V_(IN)) rangingfrom 0 to 1, which is a range wider than that of the fourth step-downconverter 400-1. Furthermore, in the fifth step-down converter 500-1, anRMS current flowing in the third switch SW3 may be reduced as comparedwith the fourth step-down converter 400-1, and an RMS current flowing inthe capacitor C may be further reduced by adjusting a duty ratio of thefirst step-down operation mode Φ₁ and the second step-down operationmode <1>₃.

A sixth step-down converter with a dual-path according to the exemplaryembodiment will be described with reference to FIGS. 33 to 35 .

FIG. 33 is a circuit diagram illustrating a configuration of the sixthstep-down converter with the dual-path according to the exemplaryembodiment. FIGS. 34A and 34B show diagrams for describing an example ofa step-down operation mode of the sixth step-down converter shown inFIG. 33 . FIGS. 35A to 35C show diagrams for describing another exampleof a step-down operation mode of the sixth step-down converter shown inFIG. 33 .

Referring to FIG. 33 , a sixth step-down converter 600-1 with adual-path (hereinafter, referred to as a “sixth step-down converter”)according to the exemplary embodiment is configured by changingpositions of some elements of the second step-down converter 200-1 andadding a fifth switch SW5. Here, a power conversion ratio(V_(OUT)/V_(IN)) of the sixth step-down converter 600-1 is in the rangeof 0 to 1.

That is, a conversion unit 630 may include an inductor I, a capacitor C,a first switch SW1, a second switch SW2, a third switch SW3, a fourthswitch SW4, and a fifth switch SW5.

One end of the inductor I is connected to a node between the firstswitch SW1 and the fourth switch SW4, and the other end thereof isconnected to a node between the fifth switch SW5 and the capacitor C.

One end of the capacitor C is connected to a node between the inductor Iand the fifth switch SW5, and the other end thereof is connected to anode between the second switch SW2 and the third switch SW3.

One end of the first switch SW1 is connected to an input unit 610, andthe other end thereof is connected to a node between the inductor I andthe fourth switch SW4.

One end of the second switch SW2 is connected to a node between thecapacitor C and the third switch SW3, and the other end thereof isconnected to a node between the fifth switch SW5 and an output unit 650.

One end of the third switch SW3 is connected to a node between thecapacitor C and the second switch SW2, and the other end thereof isconnected to a node between the fourth switch SW4 and the output unit650.

One end of the fourth switch SW4 is connected to a node between thefirst switch SW1 and the inductor I, and the other end thereof isconnected to a node between the input unit 610 and the third switch SW3.

One end of the fifth switch SW5 is connected to a node between theinductor I and the capacitor C, and the other end thereof is connectedto a node between the output unit 650 and the second switch SW2.

More specifically, the conversion unit 630 may be driven in the order ofa first step-down operation mode and a third step-down operation mode.That is, the conversion unit 630 may periodically perform an operationthat sequentially includes the first step-down operation mode and thethird step-down operation mode. As such, the conversion unit 630 maystep down and transfer power input from the input unit 610 to the outputunit 650.

That is, as shown in FIG. 34A, the conversion unit 630 may be driven inthe first step-down operation mode in which the first switch SW1 and thesecond switch SW2 are turned on and the third switch SW3, the fourthswitch SW4, and the fifth switch SW5 are turned off.

After the conversion unit 630 is driven in the first step-down operationmode, the conversion unit 630 may be driven in the third step-downoperation mode in which the first switch SW1, the third switch SW3, andthe fifth switch SW5 are turned on and the second switch SW2 and thefourth switch SW4 are turned off, as shown in FIG. 34B. Accordingly, acurrent which flows to the output unit 650 (i.e., a load) is divided andtransferred through a first current transfer path P1 using the inductorI and a second current transfer path P2 using the capacitor C.Therefore, an RMS value of the current flowing in the inductor I isreduced due to the additional current transfer path using the capacitorC.

Furthermore, the conversion unit 630 may be driven in the order of thefirst step-down operation mode and a second step-down operation mode.That is, the conversion unit 630 may periodically perform an operationthat sequentially includes the first step-down operation mode and thesecond step-down operation mode. As such, the conversion unit 630 maystep down and transfer power input from the input unit 610 to the outputunit 650.

That is, as shown in FIG. 35A, the conversion unit 630 may be driven inthe first step-down operation mode in which the first switch SW1 and thesecond switch SW2 are turned on and the third switch SW3, the fourthswitch SW4, and the fifth switch SW5 are turned off.

After the conversion unit 630 is driven in the first step-down operationmode, the conversion unit 630 may be driven in the second step-downoperation mode in which the third switch SW3, the fourth switch SW4, thefifth switch SW5 are turned on and the first switch SW1 and the secondswitch SW2 are turned off, as shown in FIG. 35C. Accordingly, a currentwhich flows to the output unit 650 (i.e., a load) is divided andtransferred through a third current transfer path P3 using the inductorI and a fourth current transfer path P4 using the capacitor C.Therefore, an RMS value of the current flowing in the inductor I isreduced due to the additional current transfer path using the capacitorC.

According to an exemplary embodiment, the conversion unit 630 may bedriven in the order of the first step-down operation mode, the thirdstep-down operation mode, and a second step-down operation mode. Thatis, the conversion unit 630 may periodically perform an operation thatsequentially includes the first step-down operation mode, the thirdstep-down operation mode, and the second step-down operation mode. Assuch, the conversion unit 630 may step down and transfer power inputfrom the input unit 610 to the output unit 650.

That is, as shown in FIG. 35A, the conversion unit 630 may be driven inthe first step-down operation mode in which the first switch SW1 and thesecond switch SW2 are turned on and the third switch SW3, the fourthswitch SW4, and the fifth switch SW5 are turned off.

After the conversion unit 630 is driven in the first step-down operationmode, the conversion unit 630 may be driven in the third step-downoperation mode in which the first switch SW1, the third switch SW3, thefifth switch SW5 are turned on and the second switch SW2 and the fourthswitch SW4 are turned off, as shown in FIG. 35B. Accordingly, a currentwhich flows to the output unit 650 (i.e., a load) is divided andtransferred through a first current transfer path P1 using the inductorI and a second current transfer path P2 using the capacitor C.Therefore, an RMS value of the current flowing in the inductor I isreduced due to the additional current transfer path using the capacitorC.

In addition, after the conversion unit 630 is driven in the thirdstep-down operation mode, the conversion unit 630 may be driven in thesecond step-down operation mode in which the third switch SW3, thefourth switch SW4, and the fifth switch SW5 are turned on and the firstswitch SW1 and the second switch SW2 are turned off, as shown in FIG.35C. Accordingly, a current flowing to the output unit 650 (i.e., theload) is divided and transferred through a third current transfer pathP3 using the inductor I and a fourth current transfer path P4 using thecapacitor 2. Therefore, an RMS value of the current flowing in theinductor I is reduced due to the additional current transfer path usingthe capacitor C.

A seventh step-down converter with a dual-path according to theexemplary embodiment will be described with reference to FIG. 36 .

FIG. 36 is a circuit diagram illustrating a configuration of the seventhstep-down converter with the dual-path according to the exemplaryembodiment.

Since a seventh step-down converter 700-1 with a dual-path (hereinafterreferred to as a “seventh step-down converter”) according to theexemplary embodiment is substantially the similar to the first step-downconverter 100-1, differences therebetween will be described.

Referring to FIG. 36 , the seventh step-down converter 700-1 accordingto the exemplary embodiment further includes three switches and onecapacitor added to the first step-down converter 100-1.

Accordingly, in the seventh step-down converter 700-1 according to theexemplary embodiment, unlike the first step-down converter 100-1,sections in which currents are supplied in parallel may be expanded totwo phases according to the exemplary embodiment.

More specifically, a conversion unit 730 may be driven in the order of afirst step-down operation mode Φ₁ and a second step-down operation modeΦ₂. That is, the conversion unit 730 may periodically perform anoperation that sequentially includes the first step-down operation modeΦ₁ and the second step-down operation mode Φ₂ and may step down andtransfer power input from an input unit 710 to an output unit 750.

That is, as shown in FIG. 36 , the conversion unit 730 may be driven inthe first step-down operation mode Φ₁ in which a current flowing to theoutput unit 750 (i.e., a load) is divided and transferred through afirst current transfer path using a capacitor and a second currenttransfer path using at least one inductor and at least one capacitor.

After the conversion unit 730 is driven in the first step-down operationmode Φ₁, the conversion unit 730 may be driven in the second step-downoperation mode Φ₂, as shown in FIG. 36 . Accordingly, a current flowingto the output unit 750 (i.e., the load) is divided and transferredthrough a third current transfer path using a capacitor and an inductorand a fourth current transfer path using a switch.

As described above, in the seventh step-down converter 700-1 accordingto the exemplary embodiment, sections in which currents are supplied inparallel may be expanded to the step-down operation modes Φ₁ and Φ₂,that is, two phases, unlike the first step-down converter 100-1.

An eighth step-down converter with a dual-path according to theexemplary embodiment will be described with reference to FIG. 37 .

FIG. 37 is a circuit diagram illustrating a configuration of the eighthstep-down converter with the dual-path according to the exemplaryembodiment.

Since an eighth step-down converter 800-1 with a dual-path (hereinafterreferred to as an “eighth step-down converter”) according to theexemplary embodiment is substantially similar to the second step-downconverter 200-1 according to the, differences therebetween will bedescribed.

Referring to FIG. 37 , the eighth step-down converter 800-1 according tothe exemplary embodiment further includes three switches and onecapacitor added to the second step-down converter 200-1.

Accordingly, in the eighth step-down converter 800-1 according to theexemplary embodiment, sections in which currents are supplied inparallel may be expanded to two phases, unlike the second step-downconverter 200-1.

More specifically, a conversion unit 830 may be driven in the order of afirst step-down operation mode Φ₁, a third step-down operation mode Φ₂,and a second step-down operation mode <1>₃. That is, the conversion unit830 may periodically perform an operation that sequentially includes thefirst step-down operation mode Φ₁, the third step-down operation modeΦ₂, and the second step-down operation mode Φ₂ and may step down andtransfer power input from an input unit 810 to an output unit 850.

That is, as shown in FIG. 37 , the conversion unit 830 may be driven inthe first step-down operation mode Φ₁. Accordingly, a current whichflows to the output unit 850 (i.e., a load) is divided and transferredthrough a first current transfer path using a capacitor and a secondcurrent transfer path using at least one inductor and at least onecapacitor.

After the conversion unit 830 is driven in the first step-down operationmode Φ₁, the conversion unit 630 may be driven in the third step-downoperation mode Φ₂, as shown in FIG. 37 . Accordingly, a current whichflows to the output unit 850 (i.e., the load) is divided and transferredthrough a third current transfer path using a capacitor and an inductorand a fourth current transfer path using a switch.

In addition, after the conversion unit 830 is driven in the thirdstep-down operation mode Φ₂, as shown in FIG. 37 , the conversion unit830 may be driven in the second step-down operation mode <1>₃.Accordingly, a current which flows to the output unit 850 (i.e., theload) is transferred through a fifth current transfer path using aninductor.

As described above, in the eighth step-down converter 800-1 according tothe exemplary embodiment, sections in which currents are supplied inparallel may be expanded to the first and third step-down operationmodes Φ₁ and Φ₂, that is, two phases, unlike the second step-downconverter 200-1 according to the exemplary embodiment

A ninth step-down converter with a dual-path according to the exemplaryembodiment will be described with reference to FIG. 38 .

FIG. 38 is a circuit diagram illustrating a configuration of the ninthstep-down converter with the dual-path according to the exemplaryembodiment.

Since a ninth step-down converter 900-1 with a dual-path (hereinafterreferred to as a “ninth step-down converter”) according to the exemplaryembodiment is substantially similar to the fourth step-down converter400-1, differences therebetween will be described.

Referring to FIG. 38 , the ninth step-down converter 900-1 according tothe exemplary embodiment further includes three switches and onecapacitor added to the fourth step-down converter 400-1.

Accordingly, in the ninth step-down converter 900-1 according to theexemplary embodiment, sections in which currents are supplied inparallel may be expanded to two phases unlike the fourth step-downconverter 400-1 according to the exemplary embodiment.

More specifically, a conversion unit 930 may be driven in the order of afirst step-down operation mode Φ₁ and a second step-down operation modeΦ₂. That is, the conversion unit 930 may periodically perform anoperation that sequentially includes the first step-down operation modeΦ₁ and the second step-down operation mode Φ₂ and may step down andtransfer power input from an input unit 910 to an output unit 950.

That is, as shown in FIG. 38 , the conversion unit 930 may be driven inthe first step-down operation mode Φ₁. Accordingly, a current whichflows to the output unit 950 (i.e., a load) is divided and transferredthrough a first current transfer path using a capacitor and a secondcurrent transfer path using at least one inductor and at least onecapacitor.

After the conversion unit 930 is driven in the first step-down operationmode Φ₁, the conversion unit 930 may be driven in the second step-downoperation mode Φ₂, as shown in FIG. 38 . Accordingly, a current whichflows to the output unit 950 (i.e., the load) is divided and transferredthrough a third current transfer path using a capacitor and an inductorand a fourth current transfer path using a capacitor.

As described above, in the ninth step-down converter 900-1 according tothe exemplary embodiment, sections in which currents are supplied inparallel may be expanded to step-down operation modes Φ₁ and Φ₂, thatis, two phases, unlike the fourth step-down converter 400-1 .

A tenth step-down converter with a dual-path according to the exemplaryembodiment will be described with reference to FIG. 39 .

FIG. 39 is a circuit diagram illustrating a configuration of the tenthstep-down converter with the dual-path according to the exemplaryembodiment.

Since a tenth step-down converter 1000-1 with a dual-path (hereinafterreferred to as a “tenth step-down converter”) according to the exemplaryembodiment is substantially similar to the fifth step-down converter500-1, differences therebetween will be described.

Referring to FIG. 39 , the tenth step-down converter 1000-1 according tothe exemplary embodiment further includes three switches and onecapacitor added to the fifth step-down converter 500-1.

Accordingly, in the tenth step-down converter 1000-1 according to theexemplary embodiment, sections in which currents are supplied inparallel may be expanded to two phases unlike the fifth step-downconverter 500-1.

More specifically, a conversion unit 1030 may be driven in the order ofa first step-down operation mode Φ₁, a third step-down operation modeΦ₂, and a second step-down operation mode <1>₃. That is, the conversionunit 1030 may periodically perform an operation that sequentiallyincludes the first step-down operation mode Φ₁, the third step-downoperation mode Φ₂, and the second step-down operation mode Φ₃and maystep down and transfer power input from an input unit 1010 to an outputunit 1050.

That is, as shown in FIG. 39 , the conversion unit 1030 may be driven inthe first step-down operation mode Φ₁. Accordingly, a current whichflows to the output unit 1050 (i.e., a load) is divided and transferredthrough a first current transfer path using a capacitor and a secondcurrent transfer path using at least one inductor and at least onecapacitor.

After the conversion unit 1030 is driven in the first step-downoperation mode Φ₁, the conversion unit 1030 may be driven in the thirdstep-down operation mode Φ₂, as shown in FIG. 39 . Accordingly, acurrent which flows to the output unit 1050 (i.e., the load) istransferred through a third current transfer path using an inductor.

In addition, after the conversion unit 1030 is driven in the thirdstep-down operation mode Φ₂, the conversion unit 1030 may be driven inthe second step-down operation mode Φ₃, as shown in FIG. 39 .Accordingly, a current which flows to the output unit 1050 (i.e., theload) is divided and transferred through a fourth current transfer pathusing a capacitor and an inductor and a fifth current transfer pathusing a capacitor.

As described above, in the tenth step-down converter 1000-1 according tothe exemplary embodiment, sections in which currents are supplied inparallel may be expanded to the first and second step-down operationmodes Φ₁ and Φ₃, that is, two phases, unlike the fifth step-downconverter 500-1.

An eleventh step-down converter with a triple-path according to theexemplary embodiment will be described with reference to FIG. 40 .

FIG. 40 is a circuit diagram illustrating a configuration of theeleventh step-down converter with the triple-path according to theexemplary embodiment.

Referring to FIG. 40 , an eleventh step-down converter 1100-1 with atriple-path (hereinafter, referred to as an “eleventh step-downconverter”) according to the exemplary embodiment is configured byexpanding the first step-down converter 100-1 so as to have threecurrent transfer paths. Here, a power conversion ratio (V_(OUT)/V_(IN))of the eleventh step-down converter 1100-1 is in the range of 0.67 to 1.

That is, a conversion unit 1130 may include an inductor I, a firstcapacitor C1, a second capacitor C2, a first switch SW1, a second switchSW2, a third switch SW3, a fourth switch SW4, a fifth switch SW5, and asixth switch SW6.

One end of the inductor I is connected to a node between the firstswitch SW1 and the first capacitor C1, and the other end thereof isconnected to a node between an output unit 1150 and the second switchSW2.

One end of the first capacitor C1 is connected to a node between thefirst switch SW1 and the inductor I, and the other end thereof isconnected to a node between the second switch SW2 and the third switchSW3.

One end of the second capacitor C2 is connected to a node between thethird switch SW3 and the fourth switch SW4, and the other end thereof isconnected to a node between the fifth switch SW5 and the sixth switchSW6.

One end of the first switch SW1 is connected to an input unit 1110, andthe other end thereof is connected to a node between the inductor I andthe first capacitor C1.

One end of the second switch SW2 is connected to a node between thefirst capacitor C1 and the third switch SW3, and the other end thereofis connected to a node between the inductor I and the output unit 1150.

One end of the third switch SW3 is connected to a node between the firstcapacitor C1 and the second switch SW2, and the other end thereof isconnected to a node between the fourth switch SW4 and the secondcapacitor C2.

One end of the fourth switch SW4 is connected to a node between theinput unit 1110 and the first switch SW1, and the other end thereof isconnected to a node between the third switch SW3 and the secondcapacitor C2.

One end of the fifth switch SW5 is connected to a node between thesecond capacitor C2 and the sixth switch SW6, and the other end thereofis connected to a node between the inductor I and the second switch SW2.

One end of the sixth switch SW6 is connected to a node between thesecond capacitor C2 and the fifth switch SW5, and the other end thereofis connected to a node between the input unit 1110 and the output unit1150.

More specifically, the conversion unit 1130 may be driven in the orderof a first step-down operation mode Φ₁ and a second step-down operationmode Φ₂. That is, the conversion unit 1130 may periodically perform anoperation that sequentially includes the first step-down operation modeΦ₁ and the second step-down operation mode Φ₂ and may step down andtransfer power input from the input unit 1110 to the output unit 1150.In this case, a duty ratio indicating a driving time of the firststep-down operation mode Φ₁ may be determined based on an input voltage,an output voltage, and the like.

That is, as shown in FIG. 40 , the conversion unit 1130 may be driven inthe first step-down operation mode Φ₁ in which the first switch SW1, thesecond switch SW2, the fourth switch SW4, and the fifth switch SW5 areturned on and the third switch SW3 and the sixth switch SW6 are turnedoff. Accordingly, a current which flows to the output unit 1150 (i.e., aload) is divided and transferred through a triple-path including a firstcurrent transfer path using the first switch SW1 and the inductor I, asecond current transfer path using the first switch SW1, the firstcapacitor C1, and the second switch SW2, and a third current transferpath using the fourth switch SW4, the second capacitor C2, and the fifthswitch SW5. Therefore, due to the additional two current transfer pathsusing the two capacitors C1 and C2, an RMS value of the current flowingin the inductor I is further reduced as compared with a dual pathstructure.

After the conversion unit 1130 is driven in the first step-downoperation mode Φ₁, the conversion unit 1130 may be driven in the secondstep-down operation mode Φ₂ in which the third switch SW3 and the sixthswitch SW6 are turned on and the first switch SW1, the second switchSW2, the fourth switch SW4, and the fifth switch SW5 are turned off, asshown in FIG. 40 .

A twelfth step-down converter with a triple-path according to theexemplary embodiment will be described with reference to FIG. 41 .

FIG. 41 is a circuit diagram illustrating a configuration of the twelfthstep-down converter with the triple-path according to the exemplaryembodiment.

Referring to FIG. 41 , a twelfth step-down converter 1200-1 with atriple-path (hereinafter, referred to as a “twelfth step-downconverter”) according to the exemplary embodiment further includes aseventh switch SW7 added to the eleventh step-down converter 1100-1.

That is, a conversion unit 1230 includes an inductor I, a firstcapacitor C1, a second capacitor C2, a first switch SW1, a second switchSW2, a third switch SW3, a fourth switch SW4, a fifth switch SW5, asixth switch SW6, and the seventh switch SW7.

One end of the seventh switch SW7 is connected to a node between aninput unit 1210 and the first switch SW1, and the other end thereof isconnected to a node between the input unit 1210 and the sixth switchSW6.

More specifically, a conversion unit 1230 may be driven in the order ofa first step-down operation mode Φ₁, a third step-down operation modeΦ₂, and a second step-down operation mode <1>₃. That is, the conversionunit 1230 may periodically perform an operation that sequentiallyincludes the first step-down operation mode Φ₁, the third step-downoperation mode Φ₂, and the second step-down operation mode Φ₁ and maystep down and transfer power input from the input unit 1210 to an outputunit 1250.

That is, as shown in FIG. 41 , the conversion unit 1230 may be driven inthe first step-down operation mode Φ₁ in which the first switch SW1, thesecond switch SW2, the fourth switch SW4, and the fifth switch SW5 areturned on and the third switch SW3, the sixth switch SW6, and theseventh SW7 are turned off. Accordingly, a current which flows to theoutput unit 1250 (i.e., a load) is divided and transferred through afirst current transfer path using the first switch SW1 and the inductorI, a second current transfer path using the first switch SW1, the firstcapacitor C1, and the second switch SW2, and a third current transferpath using the fourth switch SW4, the second capacitor C2, and the fifthswitch SW5. Therefore, due to the additional two current transfer pathsusing the two capacitors C1 and C2, an RMS value of the current flowingin the inductor I is further reduced as compared with a dual pathstructure.

After the conversion unit 1230 is driven in the first step-downoperation mode Φ₁, the conversion unit 1230 may be driven in the thirdstep-down operation mode Φ₂ in which the first switch SW1 and theseventh switch SW7 are turned on and the second switch SW2, the thirdswitch SW3, the fourth switch SW4, the fifth switch SW5, and the sixthswitch SW6 are turned off, as shown in FIG. 41 .

In addition, after the conversion unit 1230 is driven in the thirdstep-down operation mode Φ₂, the conversion unit 1230 may be driven inthe second step-down operation mode Φ₃ in which the third switch SW3 andthe sixth switch SW6 are turned on and the first switch SW1, the secondswitch SW2, the fourth switch SW4, the fifth switch SW5, and the seventhswitch SW7 are turned off, as shown in FIG. 41 .

As described above, unlike the eleventh step-down converter 1100-1according to the exemplary embodiment, the twelfth step-down converter1200-1 is driven in the third step-down operation mode by including theseventh switch SW7 and thus has a power conversion ratio(V_(OUT)/V_(IN)) ranging from 0 to 1, which is a range wider than thatof the eleventh step-down converter 1100-1. Furthermore, in the twelfthstep-down converter 1200-1, an RMS current flowing in the first switchSW1 may be further reduced as compared with the eleventh step-downconverter 1100-1, and RMS currents flowing in two capacitors C1 and C2may be further reduced by adjusting a duty ratio of the first step-downoperation mode Φ₁ and the second step-down operation mode <1>₃.

A thirteenth step-down converter having a multi-path according to theexemplary embodiment will be described with reference to FIG. 42 .

FIG. 42 is a circuit diagram illustrating a configuration of thethirteenth step-down multi-path converter according to the exemplaryembodiment.

Referring to FIG. 42 , a thirteenth step-down converter 1300-1 having amulti-path (hereinafter, referred to as a “thirteenth step-downconverter”) according to the exemplary embodiment is configured byexpanding the first step-down converter 100-1 so as to have n currenttransfer paths. Here, a power conversion ratio (V_(OUT)/V_(IN)) of thethirteenth step-down converter 1300-1 is in the range of (n-1)/n to 1.

A conversion unit 1330 may include n-1 capacitors and a plurality ofswitches.

More specifically, the conversion unit 1330 may be driven in the orderof a first step-down operation mode Φ₁ and a second step-down operationmode Φ₂. That is, the conversion unit 1330 may periodically perform anoperation that sequentially includes the first step-down operation modeΦ₁ and the second step-down operation mode Φ₂ and may step down andtransfer power input from an input unit 1310 to an output unit 1350.

That is, as shown in FIG. 42 , the conversion unit 1330 may be driven inthe first step-down operation mode Φ₁. Accordingly, a current whichflows to the output unit 1350 (i.e., a load) is divided and transferredthrough multiple paths including a current transfer path using aninductor and n-1 current transfer paths using capacitors. Therefore, dueto the additional n-1 current transfer paths using n-1 capacitors, anRMS value of the current flowing in the inductor I is further reduced.

After the conversion unit 1330 is driven in the first step-downoperation mode Φ₁, as shown in FIG. 42 , the conversion unit 1330 may bedriven in the second step-down operation mode Φ₂.

A fourteenth step-down converter with multiple paths according to theexemplar embodiment of the present invention will be described withreference to FIG. 43 .

FIG. 43 is a circuit diagram illustrating a configuration of thefourteenth step-down multi-path converter according to the exemplaryembodiment.

Referring to FIG. 43 , a fourteenth step-down converter 1400-1 withmultiple paths (hereinafter, referred to as a “fourteenth step-downconverter”) according to the exemplary embodiment further includes oneswitch added to the thirteenth step-down converter 1300-1.

More specifically, a conversion unit 1430 may be driven in the order ofa first step-down operation mode Φ₁, a third step-down operation modeΦ₂, and a second step-down operation mode <1>₃. That is, the conversionunit 1430 may periodically perform an operation that sequentiallyincludes the first step-down operation mode Φ₁, the third step-downoperation mode Φ₂, and the second step-down operation mode Φ₃ and maystep down and transfer power input from an input unit 1410 to an outputunit 1450.

That is, as shown in FIG. 43 , the conversion unit 1430 may be driven inthe first step-down operation mode Φ₁. Accordingly, a current whichflows to the output unit 1450 (i.e., a load) is divided and transferredthrough multiple paths including a current transfer path using aninductor and n-1 current transfer paths using capacitors. Therefore, dueto the additional n-1 current transfer paths using n-1 capacitors, anRMS value of the current flowing in the inductor I is further reduced.

After the conversion unit 1430 is driven in the first step-downoperation mode Φ₁, the conversion unit 1430 may be driven in the thirdstep-down operation mode Φ₂ as shown in FIG. 43 .

In addition, after the conversion unit 1430 is driven in the thirdstep-down operation mode Φ₂, the conversion unit 1430 may be driven inthe second step-down operation mode Φ₃, as shown in FIG. 43 ,

As described above, unlike the thirteenth step-down converter 1300-1,the fourteenth step-down converter 1400-1 is driven in the thirdstep-down operation mode by including the additional switch. As such,the fourteenth step-down converter 1400-1 has a power conversion ratio(V_(OUT)/V_(IN)) ranging from 0 to 1, which is a range wider than thatof the thirteenth step-down converter 1300-1. Furthermore, in thefourteenth step-down converter 1400-1, an RMS current flowing in a firstswitch SW1 may be further reduced as compared with the thirteenthstep-down converter 1300-1, and RMS currents flowing in the n-1capacitors may be further reduced by adjusting a duty ratio of the firststep-down operation mode Φ₁ and the second step-down operation mode<1>₃.

Embodiment 2: Multi-Path Step-Up Converter

Hereinafter, a multi-path converter and a control method thereofaccording to the exemplary embodiments will be described in detail withreference to FIGS. 44 to 58 .

The exemplary embodiments below relate to a multi-path converter whichperforms a function of a step-up converter configured to step up inputpower. That is, an output voltage V_(OUT) is higher than an inputvoltage V_(IN), and a current is divided and transferred to an outputterminal through a plurality of current transfer paths (for example, twocurrent transfer paths, three current transfer paths, or n currenttransfer paths) using at least one inductor and at least one capacitor.

First, a first step-up converter with a dual-path according to anexemplary embodiment will be described with reference to FIGS. 44 to 48.

FIG. 44 is a block diagram illustrating the first step-up converter witha dual-path according to the exemplary embodiment. FIG. 45 is a circuitdiagram illustrating a configuration of the first step-up convertershown in FIG. 44 . FIGS. 46A and 46B show diagrams for describing anexample of a step-up operation mode of the first step-up converter.FIGS. 47A to 47C show diagrams for describing another example of astep-up operation mode of the first step-up converter. FIGS. 48A and 48Billustrate inductor current change due to the step-up operation mode ofthe first step-up converter.

Referring to FIG. 44 , a first step-up converter 100-2 with a dual-path(hereinafter, referred as a “first step-up converter’) includes an inputunit 110 to which power is input, a conversion unit 130 which steps upthe input power, and an output unit 150 which receives and transfers thestepped-up power to an external device.

That is, the conversion unit 130 steps up the power input through theinput unit 110 and transfers the stepped-up power to the output unit150. The conversion unit 130 transfers a current to the output unit 150even while the input power is being stepped-up.

To this end, the conversion unit 130 may include a first conversioncircuit unit 131 and a second conversion circuit unit 133.

The first conversion circuit unit 131 steps up the power input throughthe input unit 110. The first conversion circuit unit 131 transfers thestepped-up power to the output unit 150.

Referring to FIG. 45 , the first conversion circuit unit 131 may includean inductor I1, a first switch SW1, a second switch SW2, and a thirdswitch SW3.

One end of the inductor I1 is connected to an input unit 110, and theother end thereof is connected to an output unit 150.

The first switch SW1 is disposed between the input unit 110 and theinductor I1. One end thereof is connected to the input unit 110, and theother end thereof is connected to the inductor I1.

The second switch SW2 is disposed between the inductor I1 and the outputunit 150. One end thereof is connected to the inductor I1, and the otherend thereof is connected to the output unit 150.

One end of the third switch SW3 is connected to a ground, and the otherend thereof is connected to a node between the inductor I1 and thesecond switch SW2.

The second conversion circuit unit 133 transfers a current to the outputunit 150 while the first conversion circuit unit 131 steps up power.

Referring to FIG. 45 , the second conversion circuit unit 133 mayinclude a fourth switch SW4, a capacitor C1, and a fifth switch SW5.

One end of the fourth switch SW4 is connected to the input unit 110, andthe other end thereof is connected to the fifth switch SW5.

One end of the capacitor C1 is connected to a node between the fourthswitch SW4 and the fifth switch SW5, and the other end thereof isconnected to a node between the first switch SW1 and the inductor I1.

One end of the fifth switch SW5 is connected to the fourth switch SW4,and the other end thereof is connected to the output unit 150.

The above-described first step-up converter 100-2 exhibitscharacteristics of a step-up converter according to a duty ratioindicating a driving time of a first step-up operation mode. Forexample, when a duty ratio is “0,” a conversion ratio is “1,” and whenthe duty ratio is “1,” the conversion ratio is infinite. Thus, the firststep-up converter 100-2 has the characteristics of the step-upconverter. A current, which flows when the capacitor C1 is connectedparallel with the inductor I1, divides a current, which flows to theinductor I1, into two currents and reduces the current of the inductorI1 by half as compared with a conventional step-up converter. Inaddition, a conduction loss is increased in the form of a square of acurrent, so when the current is reduced by half, the conduction loss isreduced to ¼, thereby increasing efficiency.

In addition, in the first step-up converter 100-2, a switch may bedesigned as a low withstanding voltage element, thereby further reducingan overlap loss caused by a switching node.

More specifically, the conversion unit 130 may be driven in the order ofa first step-up operation mode and a second step-up operation mode.

That is, as shown in FIG. 46A, the conversion unit 130 may be driven inthe first step-up operation mode in which the first switch SW1, thethird switch SW3, and the fifth switch SW5 are turned on and the secondswitch SW2 and the fourth switch SW4 are turned off. Accordingly, theconversion unit 130 may step up power input through the input unit 110using the inductor I1 and may transfer a current to the output unit 150while stepping up the power.

After the conversion unit 130 is driven in the first step-up operationmode, as shown in FIG. 46B, the conversion unit 130 may be driven in thesecond step-up operation mode in which the second switch SW2 and thefourth switch SW4 are turned on and the first switch SW1, the thirdswitch SW3, and the fifth switch SW5 are turned off. The conversion unit130 may transfer the stepped-up power to the output unit 150.

As described above, while the current of the inductor I1 is built-up inthe first step-up operation mode, a current is transferred to an outputterminal through a path including the capacitor C1. In the secondstep-up operation mode, the inductor I1 and capacitor C1 are connectedin series to transfer a current to the output terminal. Accordingly, inthe first step-up converter 100-2, since a current is transferred to theoutput terminal in all modes, the output current may be continuous.Accordingly, an RMS value of the current in the inductor may be furtherreduced as compared with a conventional step-up converter, and a rippleand switching noise of an output voltage may be greatly reduced.

On the other hand, when a duty ratio indicating a driving time of thefirst step-up operation mode is greater than a preset value (forexample, “0.5” or the like), the conversion unit 130 may be driven inthe order of the first step-up operation mode and the second step-upoperation mode and may step up the power input through the input unit110 to transfer the stepped-up power to the output unit 150. Theconversion unit 130 may transfer a current to the output unit 150 evenwhile the input power is stepped-up.

Meanwhile, when the duty ratio indicating the driving time of the firststep-up operation mode is less than the preset value (for example, “0.5”or the like), the conversion unit 130 may be driven in the order of thefirst step-up operation mode, a third step-up operation mode, and thesecond step-up operation mode.

That is, as shown in FIG. 47A, the conversion unit 130 may be driven inthe first step-up operation mode in which the first switch SW1, thethird switch SW3, and the fifth switch SW5 are turned on and the secondswitch SW2 and the fourth switch SW4 are turned off.

After the conversion unit 130 is driven in the first step-up operationmode, the conversion unit 130 may be driven in the third step-upoperation mode in which the first switch SW1, the second switch SW2, andthe fifth switch SW5 are turned on and the third switch SW3 and thefourth switch SW4 are turned off, as shown in FIG. 47B.

After the conversion unit 130 is driven in the third step-up operationmode, the conversion unit 130 may be driven in the second step-upoperation mode in which the second switch SW2 and the fourth switch SW4are turned on and the first switch SW1, the third switch SW3, and thefifth switch SW5 are turned off, as shown in FIG. 47C.

Here, when the conversion unit 130 is driven in the order of the firststep-up operation mode, the third step-up operation mode, and the secondstep-up operation mode, the conversion unit 130 may be driven in thesecond step-up operation mode for a preset time (for example, duty ratioof “0.5” or the like). For example, when a preset value used as areference for a duty ratio comparison is “0.5” and a duty ratio is“0.3,” the duty ratio is less than the preset value. Accordingly, theconversion unit 130 is driven in the order of the first step-upoperation mode, the third step-up operation mode, and the second step-upoperation mode. In this case, in order to maintain a driving time of thesecond step-up operation mode at “0.5” which is a preset time, theconversion unit 130 is driven in the first step-up operation mode for atime of “0.3,” the third step-up operation mode for a time of “0.2,” andthe second step-up operation mode for a time of “0.5.”

As described above, when the duty ratio indicating the driving time ofthe first step-up operation mode is less than the preset value (forexample, “0.5” or the like), the conversion unit 130 may be driven inthe third step-up operation mode between the first step-up operationmode and the second step-up operation mode, and thus, a time forsupplying a current to the capacitor C1 may be extended. Accordingly, anegative effect on efficiency which is caused when a large amount ofcurrent is supplied within a short time may be prevented.

Accordingly, in the first step-up converter 100-2 according to anotherexemplary embodiment, since a current is transferred to the outputterminal in all modes, a continuous output current may be exhibited.Accordingly, an RMS value of the current in the inductor may be furtherreduced as compared with the conventional step-up converter, and aripple and switching noise of an output voltage may be greatly reduced.

In other words, when the duty ratio indicating the driving time of thefirst step-up operation mode is greater than the preset value (forexample, “0.5” or the like), the conversion unit 130 may be driven inthe order of a first step-up operation mode D₁ and a second step-upoperation mode D₂, as shown in FIG. 48A.

When the duty ratio indicating the driving time of the first step-upoperation mode is less than the preset value (for example, “0.5” or thelike), the conversion unit 130 may be driven in the order of the firststep-up operation mode D₁, a third step-up operation mode D₃, and thesecond step-up operation mode D₂, as shown in FIG. 48B.

Performance of the first step-up converter according to an exemplaryembodiment will be described with reference to FIGS. 49 to 52 .

FIG. 49 shows graphs each obtained by testing the first step-upconverter according to the exemplary embodiment in an environment with aduty ratio of 0.5. FIG. 50 shows graphs each obtained by testing thefirst step-up converter according to the exemplary embodiment in anenvironment with a duty ratio of 0.7. FIG. 51 shows graphs each obtainedby testing the first step-up converter according to the exemplaryembodiment in an environment with a duty ratio of 0.4. FIG. 52 showsgraphs each obtained by testing the first step-up converter according tothe exemplary embodiment in an environment with a duty ratio of 0.2.

Referring to FIG. 49 , it can be confirmed that an average of thecurrent in the inductor of the first step-up converter 100-2 accordingto the exemplary embodiment is reduced by about half of that of theconventional step-up converter. Unlike the conventional step-upconverter in which a current flowing to an output terminal haddiscontinuity, in the first step-up converter 100-2 according to theexemplary embodiment, it may be confirmed that a current(I_(OUT))flowing to an output terminal does not drop to zero and has continuity.As a result, a ripple of an output voltage is considerably reduced ascompared with the conventional step-up converter. Therefore, performanceof a load connected to the output terminal of the first step-upconverter 100-2, that is, performance of a block using a high voltageformed by the first step-up converter 100-2, may be prevented fromdecreasing.

Referring to FIGS. 50 to 52 , it can be confirmed that the first step-upconverter 100-2 according to the exemplary embodiment shows betterperformance than the conventional converter.

A control method of the first step-up converter with the dual-pathaccording to the exemplary embodiment will be described with referenceto FIGS. 53 and 54 .

FIG. 53 is a flowchart illustrating the control method of the firststep-up converter with the dual-path according to the exemplaryembodiment.

Referring to FIG. 53 , the first step-up converter 100-2 steps up inputpower and transfers a current to the output unit while stepping up theinput power (S110-2). That is, the first step-up converter 100-2 may bedriven in a first step-up operation mode in which the first switch SW1,the third switch SW3, and the fifth switch SW5 are turned on and thesecond switch SW2 and the fourth switch SW4 are turned off.

Then, the first step-up converter 100-2 transfers the stepped-up powerto the output unit (S130-2). That is, after the first step-up converter100-2 is driven in the first step-up operation mode, the first step-upconverter 100-2 may be driven in a second step-up operation mode inwhich the second switch SW2 and the fourth switch SW4 are turned on andthe first switch SW1, the third switch SW3, and the fifth switch SW5 areturned off.

FIG. 54 is a flowchart illustrating a stepped-up power transferringoperation shown in FIG. 53 in more detail.

Referring to FIG. 54 , when a duty ratio is greater than a preset value(Yes in operation S131), the first step-up converter 100-2 may be drivenin the second step-up operation mode (S133). That is, when a duty ratioindicating a driving time of the first step-up operation mode is greaterthan the preset value (for example, “0.5” or the like), the firststep-up converter 100-2 may be driven in the second step-up operationmode.

Meanwhile, when the duty ratio is less than the preset value (No inoperation S131), the first step-up converter 100-2 may be driven in athird step-up operation mode (S135). That is, when the duty ratioindicating a driving time of the first step-up operation mode is lessthan the preset value (for example, duty ratio of “0.5” or the like),the first step-up converter 100-2 may be driven in the third step-upoperation mode in which the first switch SW1, the second switch SW2, andthe fifth switch SW5 are turned on and the third switch SW3 and thefourth switch SW4 are turned off.

Next, the first step-up converter 100-2 may be driven in the secondstep-up operation mode (S137). In this case, the first step-up converter100-2 may be driven in the second step-up operation mode for a presettime (for example, duty ratio of “0.5” or the like).

A second step-up converter with dual paths according to an embodimentwill be described with reference to FIGS. 55 and 56 .

FIG. 55 is a diagram illustrating an example of a configuration and astep-up operation mode of the second step-up converter with thedual-path according to the exemplary embodiment, and FIG. 56 is adiagram illustrating another example of a step-up operation mode of thesecond step-up converter shown in FIG. 55 .

Since a second step-up converter 200-2 with a dual-path (hereinafterreferred to as a “second step-up converter”) according to the exemplaryembodiment is substantially similar to the first step-up converter100-2, differences therebetween will be described.

Referring to FIGS. 55 and 56 , the second step-up converter 200-2according to the exemplary embodiment is configured by changingpositions of some elements of the first step-up converter 100-2.

That is, a conversion unit 230 may include an inductor I1, a capacitorC1, a first switch SW1, a second switch SW2, a third switch SW3, afourth switch SW4, and a fifth switch SW5.

One end of the inductor I1 is connected to an input unit 210, and theother end thereof is connected to a node between the second switch SW2and the third switch SW3.

One end of the capacitor C1 is connected to a node between the firstswitch SW1 and the fourth switch SW4, and the other end thereof isconnected to a node between the third switch SW3 and the fifth switchSW5.

One end of the first switch SW1 is connected to a node between the inputunit 210 and the inductor I1and the other end thereof is connected to anode between the fourth switch SW4 and the capacitor C1.

One end of the second switch SW2 is connected to a node between theinductor I1 and the third switch SW3, and the other end thereof isconnected to a node between the input unit 210 and an output unit 250.

One end of the third switch SW3 is connected to a node between theinductor I1 and the second switch SW2, and the other end thereof isconnected to a node between the capacitor C1 and the fifth switch SW5.

One end of the fourth switch SW4 is connected to a node between thefirst switch SW1 and the capacitor C1, and the other end thereof isconnected to a node between the output unit 250 and the fifth switchSW5.

One end of the fifth switch SW5 is connected to a node between thecapacitor C1 and the third switch SW3, and the other end thereof isconnected to the output unit 250.

The conversion unit 230 may be driven in the order of a first step-upoperation mode Φ₁ and a second step-up operation mode Φ₂.

That is, as shown in FIG. 55 , the conversion unit 230 may be operatedin the first step-up operation mode Φ₁ in which the first switch SW1,the second switch SW2, and the fifth switch SW5 are turned on and thethird switch SW3 and the fourth switch SW4 are turned off. Accordingly,the conversion unit 230 may step up power input through the input unit210 using the inductor I1 and may transfer a current to the output unit250 while stepping up the power.

After the conversion unit 230 is driven in the first step-up operationmode Φ₁, the conversion unit 230 may be driven in the second step-upoperation mode Φ₂ in which the third switch SW3 and the fourth switchSW4 are turned on and the first switch SW1, the second switch SW2, andthe fifth switch SW5 are turned off, as shown in FIG. 55 . Therefore,the conversion unit 230 may transfer the stepped-up power to the outputunit 250.

As described above, while the current of the inductor I1 is built-up inthe first step-up operation mode Φ₁, a current is transferred to anoutput terminal through a path including the capacitor C1. In the secondstep-up operation mode Φ₂, a current is transferred to the outputterminal through the inductor I1 and capacitor C1 connected in series.Accordingly, in the second step-up converter 200-2 according to theexemplary embodiment, a current is transferred to the output terminal inall modes, so a continuous output current is exhibited.

On the other hand, the conversion unit 230 may be driven in the order ofa first step-up operation mode Φ₁, a third step-up operation mode Φ₂,and a second step-up operation mode <1>₃.

That is, as shown in FIG. 56 , the conversion unit 230 may be operatedin the first step-up operation mode Φ₁ in which the first switch SW1,the second switch SW2, and the fifth switch SW5 are turned on andturning the third switch SW3 and the fourth switch SW4 are turned off.Accordingly, the conversion unit 230 may step up power input through theinput unit 210 using the inductor I1 and may transfer a current to theoutput unit 250 while stepping up the power.

After the conversion unit 230 is driven in the first step-up operationmode Φ₁, the conversion unit 230 may be driven in the third step-upoperation mode Φ₂ in which the first switch SW1, the third switch SW3,and the fifth switch SW5 are turned on and the second switch SW2 and thefourth switch SW4 are turned off, as shown in FIG. 56 .

After the conversion unit 230 is driven in the third step-up operationmode Φ₂, the conversion unit 230 may be driven in the second step-upoperation mode Φ₃ in which the third switch SW3 and the fourth switchSW4 are turned on and the first switch SW1, the second switch SW2, andthe fifth switch SW5 are turned off as shown in FIG. 56 . Therefore, theconversion unit 230 may transfer the stepped-up power to the output unit250.

As described above, the conversion unit 230 may be driven in the thirdstep-up operation mode Φ₂ between the first step-up operation mode Φ₁and the second step-up operation mode Φ₃, and thus, a time for supplyinga current to the capacitor C1 may be extended. Accordingly, an adverseeffect on efficiency which is caused when a large amount of current issupplied within a short time may be prevented.

Accordingly, in the second step-up converter 200-2 according to theexemplary embodiment, a current is transferred to the output terminal inall modes. As a result, a output current may be continuous. Accordingly,an RMS value of the current in the inductor may be further reduced ascompared with the conventional step-up converter, and a ripple andswitching noise of an output voltage may be greatly reduced.

A third step-up converter with a multi-path according to the exemplaryembodiment will be described with reference to FIG. 57 .

FIG. 57 is a circuit diagram illustrating a configuration of the thirdstep-up multi-path converter according to the exemplary embodiment.

Referring to FIG. 57 , a third step-up converter 300-2 with multiplepaths (hereinafter, referred to as a “third step-up converter”)according to an embodiment is configured by expanding the second step-upconverter 200-1 so as to have n current transfer paths.

More specifically, a conversion unit 330 may be driven in the order of afirst step-up operation mode Φ₁ and a second step-up operation mode Φ₂.

That is, as shown in FIG. 57 , the conversion unit 330 may be driven inthe first step-up operation mode Φ₁. Accordingly, the conversion unit330 may step up power input through an input unit 310 using an inductorI1 and may transfer a current to an output unit 350 through n currenttransfer paths using n capacitors while stepping up the power.

After the conversion unit 330 is driven in the first step-up operationmode Φ₁, the conversion unit 330 may be driven in the second step-upoperation mode Φ₂, as shown in FIG. 57 . Therefore, the conversion unit330 may transfer the stepped-up power to the output unit 350.

A fourth step-up converter with a multi-path according to an exemplaryembodiment will be described with reference to FIG. 58 .

FIG. 58 is a circuit diagram illustrating a configuration of the fourthstep-up multi-path converter according to the exemplary embodiment.

Referring to FIG. 58 , a fourth step-up converter 400-2 with multiplepaths (hereinafter, referred to as a “fourth step-up converter”)according to the embodiment is configured by expanding the first step-upconverter 100-1 to have n current transfer paths.

More specifically, a conversion unit 430 may be driven in the order of afirst step-up operation mode Φ₁ and a second step-up operation mode Φ₂.

That is, as shown in FIG. 58 , the conversion unit 430 may be driven inthe first step-up operation mode Φ₁. Accordingly, the conversion unit430 may step up power input through an input unit 410 using an inductorI1 and may transfer a current to an output unit 450 through n currenttransfer paths using n capacitors while stepping up the power

After the conversion unit 430 is driven in the first step-up operationmode Φ₁, the conversion unit 430 may be driven in the second step-upoperation mode Φ₂, as shown in FIG. 58 . Therefore, the conversion unit430 may transfer the stepped-up power to the output unit 450.

FIGS. 59A and 59B show diagrams for describing an example in which thesecond step-down converter shown in FIG. 21 is operated in a single-pathmanner. Referring to FIGS. 21 and 59 , when the second step-downconverter is operated in the single-path manner, the conversion unit 230may be driven in the order of the fourth step-down operation mode andthe fifth step-down operation mode. That is, the conversion unit 230 mayperiodically perform an operation that sequentially includes the fourthstep-down operation mode and the fifth step-down operation mode and maystep down power input from the input unit 210 and transfer thestepped-down power to the output unit 250.

That is, as shown in FIG. 59A, the conversion unit 230 may be driven inthe fourth-down operation mode in which a first switch SW1 is turned onand second to fourth switches SW2 to SW4 are turned off. Accordingly, acurrent flowing to the output unit 250 is transferred through a firstcurrent transfer path P1 using an inductor I. That is, when theconversion unit 230 is driven in the fourth step-down operation mode,the current is transferred to the output unit 250 through a singlecurrent transfer path.

After the conversion unit 230 is driven in the fourth-down operationmode, the conversion unit 230 may be driven in the fifth step-downoperation mode in which the fourth switch SW4 is turned on and the firstto third switches SW1 to SW3 are turned off, as shown in FIG. 59B.

As described above, when the conversion unit 230 is operated in thesingle-path manner, the current is transferred to the output unit 250through the single current transfer path P1 in the same manner as in aconventional step-down converter. In the following description, forconvenience of description, a manner in which a current is transferredto an output unit through a plurality of parallel current transfer pathsthat are the same as in the manner shown in FIGS. 22A to 22C will bereferred to as a multi-path manner.

FIG. 60 is a graph showing efficiencies when the second step-downconverter shown in FIG. 21 is operated in the multi-path manner (seeFIGS. 22A to 22C) and the single-path manner (see FIGS. 59A and 59B).Referring to FIG. 60 , the efficiency of the multi-path manner (e.g.,dual-path step-down converter (DPNC)) is generally higher than theefficiency of the single-path manner (e.g., conventional buck convertertopology (CBT)). However, when a current I_(LOAD) in a load is low (forexample, 0.2 A), the efficiency of the single-path manner is higher thanthe efficiency of the multi-path manner. Therefore, when the currentI_(LOAD) in the load is high, the second step-down converter may beoperated in the multi-path manner, and when the current I_(LOAD) in theload is low, the second step-down converter may be operated in thesingle-path manner. In this way, it is possible to increase the overallefficiency of the second step-down converter.

FIG. 61 is a flowchart for describing a step-down converting methodaccording to the first exemplary embodiment. Referring to FIG. 61 , thestep-down converting method includes operating a step-down converterincluding a power source, an inductor, a capacitor, and a load in amulti-path manner (S611) and operating the step-down converter in asingle-path manner (S612). Operation S611 of the operating in themulti-path manner is illustrated in the drawing as being performed priorto operation S612 of the operating in the single-path manner, butoperation S611 of the operating in the multi-path manner may beperformed after operation S612 of the operating in the single-pathmanner. In addition, after operation S611 of the operating in themulti-path manner and operation S612 of the operating in the single-pathmanner are performed, operation S611 of the operating in the multi-pathmanner and operation S612 of the operating in the single-path manner maybe repeated once or more.

Hereinafter, the step-down converting method shown in FIG. 61 will bedescribed with reference to the second step-down converter shown in FIG.21 . Operation S611 of the operating in the multi-path manner may beperformed in order of, for example, the first step-down operation mode(see FIG. 22A), the third step-down operation mode (see FIG. 22B), andthe second step-down operation mode (see FIG. 22C). In addition,operation S611 of the operating in the multi-path manner may include,for example, the first step-down operation mode (see FIG. 22A) and thesecond step-down operation mode (see FIG. 22C). Operation S612 of theoperating in the single-path manner may be performed in order of, forexample, the fourth step-down operation mode (see FIG. 59A) and thefifth step-down operation mode (see FIG. 59B).

A current I_(LOAD) flowing in a load in operation S611 of the operatingin the multi-path manner may be higher than the current I_(LOAD) flowingin the load in operation S612 of the operating in the single-pathmanner. For example, when the current I_(LOAD) in the load is more thana certain value, operation S611 of the operating in the multi-pathmanner may be performed, and when the current I_(LOAD) in the load isless than a certain value, operation S612 of the operating in thesingle-path manner may be performed. When the current I_(LOAD) is equalto the certain value, any one of operation S612 of the operating in thesingle-path manner and operation S611 of the operating in the multi-pathmanner may be performed. The certain value may be, for example, a valueof the current I_(LOAD) in the load at an intersection point between theefficiency of the multi-path manner (DPNC) and the efficiency of thesingle-path manner (CBT) of FIG. 60 or may be a certain value of acurrent which is adjacent to the intersection point. For example, whenthe current I_(LOAD) in the load is changed from less than a firstcertain value to more than the first certain value, operation S611 ofthe operating in the multi-path manner may be performed, and when thecurrent I_(LOAD) in the load is changed from more than a second certainvalue to less than the second certain value, operation S612 of theoperating in the single-path manner may be performed. In this case, thefirst certain value may be greater than the second certain value. Asdescribed above, hysteresis may be provided to prevent frequentswitching between operation S611 of the operating in the multi-pathmanner and operation S612 of the operating in the single-path manner.

In general, a current I_(LOAD) flowing in a load is related with anoperation mode of an electronic system (not shown, for example, aportable electronic device such as a smartphone or a laptop computer, ora stationary electronic device such as a personal computer or a display)including a step-down converter. Accordingly, one of operation S611 ofthe operating in the multi-path manner and operation S612 of theoperating in the single-path manner may be performed according to theoperation mode of the electronic system. For example, when theelectronic system is in a normal operation mode or a maximum performancemode, the current I_(LOAD) flowing in the load has a high value. Whenthe electronic system is in a power saving mode or an idle mode, thecurrent I_(LOAD) flowing in the load has a low value. Therefore, whenthe electronic system is in the normal operation mode or the maximumperformance mode, operation S611 of the operating in the multi-pathmanner may be performed. When the electronic system is in the powersaving mode or the idle mode, operation S612 of the operating in thesingle-path manner may be performed. In other words, operation S611 ofthe operating in the multi-path manner may be performed when theelectronic system is operated in the normal operation mode or themaximum performance mode. On the other hand, operation S612 of theoperating in the single-path manner may be performed when the electronicsystem is operated in the power saving mode or the idle mode.

In addition, the current I_(LOAD) flowing in the load is related with anexecution function (e.g., audio output, video output, cellularcommunication, Wi-Fi communication, etc.) of the electronic system.Accordingly, one of operation S611 of the operating in the multi-pathmanner and operation S612 of the operating in the single-path manner maybe performed according to the execution function of the electronicsystem. For example, when the electronic system performs the videooutput function, the current I_(LOAD) flowing in the load may have ahigh value. When the electronic system performs the audio outputfunction, the current I_(LOAD) flowing in the load may have a low value.Accordingly, when the electronic system performs the video outputfunction, operation S611 of the operating in the multi-path manner maybe performed. When the electronic system performs the audio outputfunction, operation S612 of the operating in the single-path manner maybe performed. In other words, the electronic system performs the videooutput function in operation S611 of the operating in the multi-pathmanner. The electronic system performs the audio output function inoperation S612 of the operating in the single-path manner. For anotherexample, when the electronic system performs video output function,audio output function and the like, operation S611 of the operating inthe multi-path manner may be performed. When the electronic system doesnot perform such functions, operation S612 of the operating in thesingle-path manner may be performed. For the same reason as describedabove, one of operation S611 of the operating in the multi-path mannerand operation S612 of the operating in the single-path manner may beperformed according to a combination of the execution functions of theelectronic system.

While the step-down converting method of FIG. 61 has been described withreference to the second step-down converter shown in FIG. 21 , thestep-down converting method may be applicable to step-down converterswith a plurality of various transfer paths. For example, the step-downconverting method of the third step-down converter (see FIG. 26 ) mayalso include operating the third step-down converter in the multi-pathmanner (S611) and operating the third step-down converter in thesingle-path manner (S612). Operation S611 of the operating in themulti-path manner may be performed in the order of the first step-downoperation mode (see FIG. 27A) and the second step-down operation mode(see FIG. 27B). Operation S612 of the operating in the single-pathmanner may be performed in the order of the fourth step-down operationmode (in which the first switch SW1 is turned on and the second to sixthswitches SW2 to SW6 are turned off in the third step-down converter ofFIG. 26 ) and the fifth step-down operation mode (in which the fourth tosixth switches SW4 to SW6 are turned on and the first to third switchesSW1 to SW3 are turned off in the third step-down converter of FIG. 26 ).

For example, the step-down converting method of the fifth step-downconverter (see FIG. 31 ) may also including operating the fifthstep-down converter in the multi-path manner (S611) and operating thefifth step-down converter in the single-path manner (S612). OperationS611 of the operating in the multi-path manner may be performed in theorder of the first step-down operation mode (see FIG. 32A), the thirdstep-down operation mode (see FIG. 32B), and the second step-downoperation mode (see FIG. 32C). Operation S612 of the operating in thesingle-path manner may include the fourth step-down operation mode (inwhich the fourth switch SW4 is turned on and the first to third switchesSW1 to SW3 are turned off in the fifth step-down converter of FIG. 31 )and the fifth step-down operation mode (in which the third switch SW3 isturned on and the first, second, and fourth switches SW1, SW2, and SW4are turned off in the fifth step-down converter of FIG. 31 ).

For example, the step-down converting method of the sixth step-downconverter (see FIG. 33 ) may also include operating the sixth step-downconverter in the multi-path manner (S611) and operating the sixthstep-down converter in the single-path manner (S612). Operation S611 ofthe operating in the multi-path manner may be performed in the order ofthe first step-down operation mode (see FIG. 35A), the third step-downoperation mode (see FIG. 35B), and the second step-down operation mode(see FIG. 35C). Alternatively, operation S611 of the operating in themulti-path manner may be performed in the order of the first step-downoperation mode (see FIG. 35A), and the second step-down operation mode(see FIG. 35C). Also, operation S611 of the operating in the multi-pathmanner may be performed in the order of the first step-down operationmode (see FIG. 34A), and the third step-down operation mode (see FIG.34B). Operation S612 of the operating in the single-path manner mayinclude the fourth step-down operation mode (in which the first andfifth switches SW1 and SW5 are turned on and the second to fourthswitches SW2 to SW4 are turned off in the sixth step-down converter ofFIG. 33 ) and the fifth step-down operation mode (in which the fourthand fifth switches SW4 and SW5 are turned on and the first to thirdswitches SW1 to SW3 are turned off in the sixth step-down converter ofFIG. 33 ).

By referencing the above-described contents, those skilled in the artmay understand that other step-down converters shown in the drawings mayalso be operated in the single path manner, and thus detaileddescriptions thereof will be omitted for convenience of description. Inaddition, in the case of the exemplary embodiment (see FIG. 10 )including the conventional converter module 10 and the conversion unit130 with a plurality of parallel current transfer paths, operation S611of the operating in the multi-path manner may be performed using theconversion unit 130 with the plurality of parallel current transferpaths, and operation S612 of the operating in the single-path manner maybe performed using the conventional converter module 10.

FIG. 62 is a graph showing efficiencies when the second step-downconverter shown in FIG. 21 is operated in a two-phase manner and athree-phase manner. Here, the second step-down converter being operatedin the two-phase manner means that the second step-down converterperiodically performs an operation that sequentially includes the firststep-down operation mode (see FIG. 22A) and the second step-downoperation mode (see FIG. 22C). In addition, the second step-downconverter being operated in the three-phase manner means that the secondstep-down converter periodically performs an operation that sequentiallyincludes the first step-down operation mode (see FIG. 22A), the thirdstep-down operation mode (see FIG. 22B), and the second step-downoperation mode (see FIG. 22C). Referring to FIG. 62 , when a ratio(V_(OUT)/V_(IN)) of an output voltage to an input voltage is high, theefficiency of the two-phase manner (DPNC-2ΦMode) is higher than theefficiency of the three-phase manner (DPNC-3Φ Mode). In addition, whenthe ratio (V_(OUT)/V_(IN)) of the output voltage to the input voltage islow, the efficiency of the three-phase manner (DPNC-3Φ Mode) is higherthan the efficiency of the two-phase manner (DPNC-2ΦMode). Therefore,when the ratio (V_(OUT)/V_(IN)) of the input voltage to the outputvoltage is high, the second step-down converter may be operated in thetwo-phase manner, and when the ratio (V_(OUT)/V_(IN)) of the inputvoltage to the output voltage is low, the second step-down converter maybe operated in the three-phase manner. In this way, it is possible toincrease the overall efficiency of the second step-down converter.

FIG. 63 is a flowchart for describing a step-down converting methodaccording to a second exemplary embodiment. Referring to FIG. 63 , thestep-down converting method includes operating a step-down converterincluding a power source, an inductor, a capacitor, and a load in atwo-phase manner (S631) and operating the step-down converter in athree-phase manner (S632). FIG. 63 shows that operation S631 of theoperating in the two-phase manner is performed prior to operation S632of the operating in the three-phase manner, but operation S631 of theoperating in the two-phase manner may be performed after operation S632of the operating in the three-phase manner. In addition, after operationS631 of the operating in the two-phase manner and operation S632 of theoperating in the three-phase manner are performed, operation S631 of theoperating in the two-phase manner and operation S632 of the operating inthe three-phase manner may be repeated once or more. Operation S631 ofthe operating in the two-phase manner may include driving the step-downconverter in a first step-down operation mode (S633) and driving thestep-down converter in a second step-down operation mode (S634). Inaddition, operation S632 of the operating in the three-phase manner mayinclude driving the step-down converter in the first step-down operationmode (S633), driving the step-down converter in a third step-downoperation mode (S635), and driving the step-down converter in the secondstep-down operation mode (S634).

Hereinafter, the step-down converting method shown in FIG. 63 will bedescribed with reference to the second step-down converter shown in FIG.21 . Operation S631 of the operating in the two-phase manner may includedriving the step-down converter in the first step-down operation mode(see FIG. 22A) (S633) and driving the step-down converter in the secondstep-down operation mode (see FIG. 22C) (S634). In addition, operationS632 of the operating in the three-phase manner may include driving thestep-down converter in the first step-down operation mode (see FIG. 22A)(S633), driving the step-down converter in the third step-down operationmode (see FIG. 22B) (S635), and driving the step-down converter in thesecond step-down operation mode (see FIG. 22C) (S634).

A ratio (V_(OUT)/V_(IN)) of an output voltage to an input voltage inoperation S631 of the operating in the two-phase manner may be higherthan a ratio (V_(OUT)/V_(IN)) of an output voltage to an input voltagein operation S632 of the operating in the three-phase manner. Forexample, when the ratio (V_(OUT)/V_(IN)) of the output voltage to theinput voltage is more than a certain value, operation S631 of theoperating in the two-phase manner may be performed. When the ratio(V_(OUT)/V_(IN)) of the output voltage to the input voltage is less thana certain value, operation S632 of the operating in the three-phasemanner may be performed. The certain value may be, for example, a valueof the ratio (V_(OUT)/V_(IN)) of the output voltage to the input voltageat an intersection point between the efficiency of the two-phase manner(DPNC-2Φ Mode) and the efficiency of the three-phase manner (DPNC-3ΦMode) of FIG. 62 or may be a certain value adjacent to the value of theintersection. For example, when the ratio (V_(OUT)/V_(IN)) of the outputvoltage to the input voltage is changed from less than a first certainvalue to more than the first certain value, operation S631 of theoperating in the two-phase manner may be performed. When the ratio(V_(OUT)/V_(IN)) of the output voltage to the input voltage is changedfrom more than a second certain value to less than the second certainvalue, operation S632 of the operating in the three-phase manner may beperformed. In this case, the first certain value may be smaller than thesecond certain value. As described above, hysteresis may be provided toprevent frequent switching between operation S631 of the operating inthe two-phase manner and operation S632 of the operating in thethree-phase manner.

In many cases, since the input voltage V_(IN) has a fixed value, theratio (V_(OUT)/V_(IN)) of the output voltage to the input voltage isproportional to the output voltage V_(OUT). Therefore, the descriptionin relation to the ratio (V_(OUT)/V_(IN)) of the output voltage to theinput voltage may also be applied to the output voltage V_(OUT). Forexample, the output voltage V_(OUT) in operation S631 of the operatingin the two-phase manner may be higher than the output voltage V_(OUT) inoperation S632 of the operating in the three-phase manner. In otherwords, one of operation S631 of the operating in the two-phase mannerand operation S632 of the operating in the three-phase manner may beselected and performed according to the output voltage V_(OUT) of thestep-down converter. For example, one of operation S631 of the operatingin the two-phase manner and operation S632 of the operating in thethree-phase manner may be selected and performed according to a value ofthe output voltage V_(OUT) of the step-down converter set by a processor(not shown) which controls the step-down converter. For example, whenthe output voltage V_(OUT) is more than a certain value, operation S631of the operating in the two-phase manner may be performed. When theoutput voltage V_(OUT) is less than a certain value, operation S632 ofthe operating in the three-phase manner may be performed. In addition,when an electronic system (not shown) including a step-down converter isin a normal operation mode or a maximum performance mode, a high outputvoltage V_(OUT) may be required, and when the electronic system (notshown) is in a power saving mode or an idle mode, a low output voltageV_(OUT) may be required. Accordingly, when the electronic system is inthe normal operation mode or the maximum performance mode, operationS631 of the operating in the two-phase manner may be performed, and whenthe electronic system is in the power saving mode or the idle mode,operation S632 of the operating in the three-phase manner may beperformed. In other words, operation S631 of the operating in thetwo-phase manner may be performed when the electronic system is operatedin the normal operation mode or the maximum performance mode, andoperation S632 of the operating in the three-phase manner may beperformed when the electronic system is operated in the power savingmode or the idle mode. In addition, a required output voltage V_(OUT)may be determined according to execution functions or a combination ofthe execution functions of the electronic system, and thus, any one ofoperation S631 of the operating in the two-phase manner and operationS632 of the operating in the three-phase manner may be performedaccording to the execution functions or the combination of the executionfunctions of the electronic system.

While the step-down converting method of FIG. 63 has been described withreference to the second step-down converter shown in FIG. 21 , thestep-down converting method may be applicable to step-down converterswith a plurality of various transfer paths. For example, the step-downconverting method of the fifth step-down converter (see FIG. 31 ) may beperformed by operating the fifth step-down converter in the two-phasemanner (S631) and then operating the fifth step-down converter in thethree-phase manner (S632). Operation S631 of the operating in thetwo-phase manner may be performed in the order of driving the fifthstep-down converter in the first step-down operation mode (see FIG. 32A)(S633) and driving the fifth step-down converter in the second step-downoperation mode (see FIG. 32C) (S634). In addition, operation S632 of theoperating in the three-phase manner may be performed in order of drivingthe fifth step-down converter in the first step-down operation mode (seeFIG. 32A) (S633), driving the fifth step-down converter in the thirdstep-down operation mode (see FIG. 32B) (S635), and driving thestep-down converter in the second step-down operation mode (see FIG.32C) (S634).

For example, the step-down converting method of the sixth step-downconverter (see FIG. 33 ) may be performed in order of operating thesixth step-down converter in the two-phase manner (S631) and operatingthe sixth step-down converter in the three-phase manner (S632).Operation S631 of the operating in the two-phase manner may be performedin order of driving the sixth step-down converter in the first step-downoperation mode (see FIG. 35A) (S633) and driving the sixth step-downconverter in the second step-down operation mode (see FIG. 35C) (S634).Alternatively, operation S631 of the operating in the two-phase mannermay be performed in order of driving the sixth step-down converter inthe first step-down operation mode (see FIG. 35A) (S633) and driving thesixth step-down converter in the third step-down operation mode (seeFIG. 35B) (S635). In addition, operation S632 of the operating in thethree-phase manner may be performed in order of driving the sixthstep-down converter in the first step-down operation mode (see FIG. 35A)(S633), driving the sixth step-down converter in the third step-downoperation mode (see FIG. 35B) (S635), and driving the step-downconverter in the second step-down operation mode (see FIG. 35C) (S634).

By referencing the above-described contents, those skilled in the artmay understand that other step-down converters shown in the drawings mayalso be operated in the two-phase manner and the three-phase manner, andthus detailed descriptions thereof will be omitted for convenience ofdescription.

Operation S631 of operating the step-down converter in the two-phasemanner and operation S632 of operating the step-down converter in thethree-phase manner may be included in operation S611 of operating thestep-down converter in the multi-path manner shown in FIG. 61 . That is,operation S611 of the operating in the multi-path manner may includeoperation S631 of operating the step-down converter in the two-phasemanner and operation S632 of operating the step-down converter in thethree-phase manner. In addition, operation S611 of the operating in themulti-path manner may include operation S631 of operating the step-downconverter in the two-phase manner or operation S632 of operating thestep-down converter in the three-phase manner. Furthermore, operationS611 of the operating in the multi-path manner may include a pluralityof operations S631 of operating the step-down converter in the two-phasemanner and a plurality of operations S632 of operating the step-downconverter in the three-phase manner.

The exemplary embodiments described above include circuits for a DC-DCconverter, but the present invention is not limited thereto and may beequally applied to an AC-AC converter, a DC-AC converter, and an AC-DCconverter according to exemplary embodiments.

The inventive concept is not limited to the above-described exemplaryembodiments. Those skilled in the art may variously modify the exemplaryembodiments without departing from the gist of the invention claimed bythe appended claims and the modifications are within the scope of theclaims.

1. A step-down converting method comprising: controlling a step-downconverter including an inductor and a capacitor such that the step-downconverter switches between a multi-path manner and a single-path manner,wherein a current is transferred to a load through a plurality ofparallel current transfer paths in the multi-path manner, and a currentis transferred to the load through a single current transfer path in thesingle-path manner, and wherein the multi-path manner includes: a firststep-down operation mode in which a current is supplied in a first pathfrom a power source to the load through the inductor and the capacitor,the capacitor being connected to the inductor in series; and a secondstep-down operation mode in which a current is supplied in a second pathfrom the inductor to the load without flowing through the capacitor, anda current is supplied in a third path from the capacitor to the loadwithout flowing through the inductor.